Thanks for the information, Fiverr. If this in relation to generating a tick-based MT5 HCC file, this reference also has some useful information: https://www.mql5.com/en/articles/75
The latter article seems to suggest that MT5 takes a series of points from the source data to create the back-test data (similar to MT4). There seems to be no suggestion so far that it will natively handle pure tick data, however.