I have a 1788 Massachusetts cent. The obverse is like around G6 and the reverse F12/15.
My question is not about the precise grade, but whether it is reasonable to split grade a colonial? Is there some other metric involved? Again the exact grade is not the issue for now, but whether splitting grades is customary for colonial coinage valuation.
Absolutely, most EAC/C4 members do that as well, of course many are also net listed with the problems spelled out like: F12/VF25 light pitting on obverse with dark toning.
EDIT: I should have said; F12/VF25 NET F15 with some light pitting on obverse with dark toning.
IF you can try and get a copy of the EAC Grading guide, I know Chris McCawley at Frisco Mint https://www.earlycents.com/ still had a few copies left, but it's been awhile since I talked to them on books. It's an excellent guide to learning more about the EAC grading tips and (not really - secrets, but some seem to think they are), The EAC/C4 crowd tends to grade much more strictly than any third party slabbing company and also (IMO) more fairly than them as well, though the grades seem lower to many collectors, it's just due to the honest descriptions I tend to think.
"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013! ANA Life Member #3288 in good standing since 1982, EAC Member #6202, NBS Member, 2¢ variety collector.