versions used for comparison tests were:
A6.60 Commercial
and
A7.80.1 Commercial

There are obvious collision-related differences between the old and new implementations, so some focus may go there.

The older implementation was intentionally written using the older collision functions, because, at the time, it seemed that the newer collision instructions offered too great of a performance hit for a large number of actors.
(It would seem a 'quick' collision toggle was written into the older implementation, so that old and new collision instructions could be swapped.)
In memory servers, there is evidence which might suggest that other users thought similarly. Use of the forum search function, might yield entries of relevance. Certainly, a few names come to mind.

With an upgrade / update to the newer A7 version, the desirable mix might have included the supposedly increased flexibility of Lite-C, with most of the speed of the previous version (A6), for similar implementations.