Just checked after I read your post and yes, it seems to have gone up a lot. Might be a good idea to ring and see if you can get a better price.
I wonder if Trinity have any of the reclaimed stuff in. I've used all types of their lower grades and even the 97% min that showed 0.9% water didn't really show any less yield.
Unless you use ASM most of the water in the methoxide comes from the catalyst/methanol reaction, not from the original water in the methanol.
And no, it doesn't happen every Winter.