The table under "Stats - Totals" in the Orc breeding wiki page is somewhat misleading. It states "These don't include the improvements the player chooses with Balia.", which would relate to improvements in strength, intelligence or discipline. But those values (5-4-3) for sapience, attractiveness and magic are the maximum that you can achieve before chapter 4 - already accounting for possible benefits from Orc research and Balia's RP.
Another table above that section demonstrates that the best starting stats you can achieve with all the unique orcs (including Implevon and the Zirantian orc corpse) are 2-2-1. Initiating "Orc Evolution" with Balia will grant +1 to all three stats, and you gain another +1 sapience if you're able to achieve the best result in Orcent's transformation. Thus the total would be 4-3-2 after "Govern Yhilin III". If you then talk to Orcent about the army after returning from Eustrin and have Balia RP≥70, you receive another +1 to these stats, bringing them to the aforementioned 5-4-3. (It's probably safe to assume that - due to the prerequisites involved - your Orc strength/intelligence/discipline would be 9-10-10 at this point, before the Third Arclent War.)
As you stated, the bonuses for the secondary stats in chapter four are +3/+1/+2 (from Patty, the Ghenalese volunteers and the conversation with Stark). So maximum legit values for sapience/attractiveness/magic are in fact 8-5-5 during the beginning of chapter five, and up to the Second Gathering.
This also means that with 7-5-5 you're actually just one (sapience) point short of the optimum. Maybe you missed talking to Implevon in time to achieve the bonus from Orcent's transformation?
I think you'd be relatively "safe" to edit your save file to 8-5-5, but 10-7-6 is definitely beyond what you could achieve in normal gameplay.