My 12 FV .223 has almost the same chamber depth as one of my range buddy's 12 FV .223.
My loads for the 77 SMKs are at 2.298 to 2.309 and the 2.309 is about 0.009 off the lands and is the deepest I have seated the bullets out.
The 77 TMKs have a longer tip, so the O.A.L.s are longer
but the cartridge base to ogive is almost the same as for the 77 SMKs.
O.A.L.s of 2.339 to 2.340 are around the 0.020 jump with the 77 TMKs and I have loaded out to a longs as 2.353 just to see if getting closer to the lands improves accuracy. It didn't. The best loads, under 0.250, are all between 2.339 and 2.343 O.A.L. The next best loads, groups around 0.260, are about 0.005 closer or further from the lands.

Our chambers really aren't that much different.
It is very possible that you have a slightly shorter chamber.
When a chamber cutting reamer wears, they would have to reset their cutting depth for the new reamer. It is possible that the reamer for your barrel was a bit shorter and they didn't adjust it enough.
Actually, your chamber is closer to SAAMI specs than ours.

I have about 1,600 rounds down my 12 FV .223 barrel, but I don't see the same rate of wear on the .223 chamber that I have seen with the 6.5mm Creedmoor after about the same number of rounds (0.036 deeper than when it was new).