Note: Access / VBA do cAsElEsS comparisons when using the '=' operator.
To get CaSeSeNsItIvE comparisons, I suggest you use the StrComp function with the vbBinaryCompare option selected. Example reworked LOC:
If StrComp(Mid(InkNew.Value, i, 1), Mid(InkOld.Value, i, 1), vbBinaryCompare) <> 0 Then