Sorry, also mash temp of 152, roughly 2Q/lb mash thickness.
IMO it’s better to have fewer active yeasts than more inactive yeasts. I’d bet chilling and decanting was your problem. If you properly rehydrate dry yeast, you’ll get ~90%+ viability, and 20b cells per gram. Proper temp is in the 100-105F range, but that varies a bit by strain. IIRC viability will drop by ~10% with every ~10 drop in rehydration temp, but that might not be exactly linear.
It’s partially a WAG, but I’d bet you’d have been better off just rehydrating and splitting the packet between the two.
Ok, I hear ya, but I pitched almost a cup of slurry! Most say that is borderline over pitching! It’s just weird.