There is a difference in GPS chipset between 37xx and 34xx. You can expect, that different hardware will lead to different results, which can't be corrected by firmware.
I don't understand this obsession on accuracy value. This is some kind of synthetic number, for which we even don't know if values from different firmware are directly comparable. I think there is accuracy value in signal logs. As it happened, the best recorded accuracy was for firmware 37xx v3.60, which measured the worst signal quality.