Does anyone know

why the strategy variation indices for the Ill 18 using HiLo for single deck H17 are different in Blackjack Attack, 2E (pg 195) and Professional Blackjack (pg 255).

For example:
standing on 16 v 10 at either 0 or 1
doubling on 10 v A at either 2 or 3

There about 9 differences just in the Ill 18. I assume these are due to different ways that the TC is rounded. Is this correct?

Thanks