Given that the AT 15A will be the only tank at tier 7 to with the OQ17-pdr with the old/low pen values, I feel as it would be safe to increase the pen values.
Penetration: 171/239/38 ->200/244/44
(Edited to include the mediums and heavy with "OQF 17-pdr Gun Mk. VII" gun)
AC 4 Experimental
Sherman VC Firefly
Sherman Firefly
Sherman Firefly Boilermaker
Sentinel AC IV Experimental
A43 Black Prince prototype
TOG II*