16. The system of claim 15 , wherein the processing unit, when executing the program instructions stored on the computer-readable storage medium via the computer readable memory, further refines the table comparisons in the merged node list via the at least one additional longest common subsequence by: mapping first table metadata from the first DITA document to the merged node list column names via the first column name map and from the second DITA document to the merged node list column names via the second column name map; constructing unique column header labels for the table segments in the table node list; and comparing the constructed column header labels of the tables via a third phase longest common subsequence process to generate a third phase merged table node list for use in the step of building the merged document object model from the merged node list and the refined table comparisons.
16. The system of claim 15 , wherein the processing unit, when executing the program instructions stored on the computer-readable storage medium via the computer readable memory, further refines the table comparisons in the merged node list via the at least one additional longest common subsequence by: mapping first table metadata from the first DITA document to the merged node list column names via the first column name map and from the second DITA document to the merged node list column names via the second column name map; constructing unique column header labels for the table segments in the table node list; and comparing the constructed column header labels of the tables via a third phase longest common subsequence process to generate a third phase merged table node list for use in the step of building the merged document object model from the merged node list and the refined table comparisons. 17. The system of claim 16 , wherein the processing unit, when executing the program instructions stored on the computer-readable storage medium via the computer readable memory, further: determines that word phrases in the node text content match if a threshold number of words of compared phrases match in the first phase longest common subsequence comparison process, and indicates word level differences as word-level highlighting mark-ups within matching compared phrases; compares table headers in the second phase longest common subsequence process, and tags and aligns matching columns as a function of comparing the table headers; and re-merges table data with tagged columns in the third phase longest common subsequence process so that the tagged columns stay aligned.