Hi Sir/Ma'am

Appreciate this is above my grade but does anyone know why these blocks have been altered to normal motion?

The 1999 Condensed says slow motion, the 1993 15 Vol says slow motion as does a soft copy of the 1965 Art of Self Defence encyclopedia, (but that also says 26 is in slow motion too?)

Just wondered as I'm aware of reasons for some move changes in other patterns such a the dodging kick in Ko-Dang but not this change.  Any information appreciated.