diff --git a/ravenframework/utils/InputData.py b/ravenframework/utils/InputData.py
index 040d54c8a4..c4aeca69ba 100644
--- a/ravenframework/utils/InputData.py
+++ b/ravenframework/utils/InputData.py
@@ -148,9 +148,13 @@ def __init__(self):
       create new instance.
       @ Out, None
     """
-    self.parameterValues = {}
-    self.subparts = []
-    self.value = ""
+    self.parameterValues = {} # attributes of the hierarchal input, attached to nodes, but not nodes themselves
+    self.subparts = []        # pre-defined nodes that are children of this node
+    self.value = ""           # non-hierarchal value associated with this node
+    # addtionalInput is a List of raven.utils.TreeStructure.InputNode instances. Unlike subparts, these do not have
+    #   a predefined structure, and will not directly be parsed as part of the spec. Only used when
+    #   strictMode is set to False for this node.
+    self.additionalInput = []
 
   @classmethod
   def createClass(cls, name, ordered=False, contentType=None, baseNode=None,
@@ -464,10 +468,12 @@ def handleError(s):
       subs = self.subs
     # read in subnodes
     subNames = set()
+    # loop over each of the nodes in the input and find matches in the defined spec
     for child in node:
       childName = child.tag
       subsSet = self._subDict.get(childName,set())
       foundSubs = 0
+      # loop over defined spec subs and see if there's a match for the input node
       for sub in subsSet:
         if sub._checkCanRead is None:
           subInstance = sub()
@@ -482,6 +488,8 @@ def handleError(s):
       elif self.strictMode:
         allowed = [s.getName() for s in subs]
         handleError(f'Unrecognized input node "{childName}"! Allowed: [{", ".join(allowed)}], tried [{", ".join(subsSet)}]')
+      else:
+        self.additionalInput.append(child)
     if self.strictMode:
       nodeNames = set([child.tag for child in node])
       if nodeNames != subNames:
diff --git a/tests/cluster_tests/AdaptiveSobol/test_adapt_sobol_parallel.xml b/tests/cluster_tests/AdaptiveSobol/test_adapt_sobol_parallel.xml
index a3f919569f..e8024edb2d 100644
--- a/tests/cluster_tests/AdaptiveSobol/test_adapt_sobol_parallel.xml
+++ b/tests/cluster_tests/AdaptiveSobol/test_adapt_sobol_parallel.xml
@@ -4,8 +4,7 @@
     <WorkingDir>workdir</WorkingDir>
     <Sequence>make,train,print</Sequence>
     <batchSize>3</batchSize>
-    <internalParallel>True</internalParallel>
-    <expectedTime>00:10:00</expectedTime>
+    <expectedTime>00:20:00</expectedTime>
     <JobName>test_qsub</JobName>
     <mode>
       mpi
@@ -14,8 +13,8 @@
   </RunInfo>
 
   <Steps>
-    <MultiRun name="make" pauseAtEnd="False">
-      <Input class="DataObjects" type="PointSet">dummyIN</Input>
+    <MultiRun name="make">
+      <Input class="DataObjects" type="PointSet">placeholder</Input>
       <Model class="Models" type="ExternalModel">poly</Model>
       <Sampler class="Samplers" type="AdaptiveSobol">sobol</Sampler>
       <Output class="DataObjects" type="PointSet">solns</Output>
@@ -65,7 +64,6 @@
   </Samplers>
 
   <Models>
-    <Dummy name="MyDummy" print="True" subType=""/>
     <ExternalModel ModuleToLoad="../multi" name="poly" subType="">
       <inputs>x1,x2,x3,x4</inputs>
       <outputs>ans,ans2</outputs>
@@ -80,10 +78,7 @@
   </Models>
 
   <DataObjects>
-    <PointSet name="dummyIN">
-      <Input>x1,x2,x3,x4</Input>
-      <Output>OutputPlaceHolder</Output>
-    </PointSet>
+    <PointSet name="placeholder"/>
     <PointSet name="solns">
       <Input>x1,x2,x3,x4</Input>
       <Output>ans,ans2</Output>
diff --git a/tests/framework/unit_tests/utils/testInputData.py b/tests/framework/unit_tests/utils/testInputData.py
index 94f39a61ba..96dbb132a3 100644
--- a/tests/framework/unit_tests/utils/testInputData.py
+++ b/tests/framework/unit_tests/utils/testInputData.py
@@ -18,19 +18,66 @@
 ravenPath = os.path.join(os.path.dirname(__file__), *(['..']*4))
 sys.path.append(ravenPath)
 
-from ravenframework.utils import InputData
+from ravenframework.utils import InputData, TreeStructure
+import xml.etree.ElementTree as ET
 print('Testing:', InputData)
 
 results = {'pass':0, 'fail':0}
 
+
+
 ####################################
-# Test InputData creating LaTeX
+# Test arbitrary XML spec
 #
+# Write the spec
+ASpec = InputData.parameterInputFactory('A', descr='first')
+BSpec = InputData.parameterInputFactory('B', descr='second')
+BSpec.setStrictMode(False)
+ASpec.addSub(BSpec)
+# Write the tree
+# <A>
+#   <B>
+#     <TheQuestion really='True'>unknown</TheQuestion>
+#     <TheAnswer>42</TheAnswer>
+#   </B>
+# </A>
+ANode = TreeStructure.InputNode('A')
+BNode = TreeStructure.InputNode('B')
+TQNode = TreeStructure.InputNode('TheQuestion', attrib={'really': 'True'}, text='unknown')
+BNode.append(TQNode)
+TANode = TreeStructure.InputNode('TheAnswer', text='42')
+BNode.append(TANode)
+ANode.append(BNode)
+# parse and check
+A = ASpec()
+A.parseNode(ANode)
+B = A.findFirst('B')
+
+if B.additionalInput[0].tag == 'TheQuestion' and \
+      B.additionalInput[0].attrib['really'] == 'True' and\
+      B.additionalInput[0].text == 'unknown':
+  results['pass'] += 1
+else:
+  print('InputData Arbitrary Custom XML 0 did not match!')
+  results['fail'] += 1
+
+if B.additionalInput[1].tag == 'TheAnswer' and \
+      B.additionalInput[1].text == '42':
+  results['pass'] += 1
+else:
+  print('InputData Arbitrary Custom XML 1 did not match!')
+  results['fail'] += 1
+
+
+####################################
 # load libraries for all of RAVEN
 from ravenframework.CustomDrivers import DriverUtils
 DriverUtils.doSetup()
 DriverUtils.setupBuiltins()
 
+####################################
+# Test InputData creating LaTeX
+#
 # test MultiRun Step
 from ravenframework import Steps