To be honest I don’t see the difference between 8 months vs 12 months in terms of wishlist duration; it’s not like they go ‘omg, this person’s wish is expiring soon, quick offer them a bag!’
I’ve often heard (from SAs and an ASM at all stores except Selfridges) that “the system” allocates bags based on the specs listed in the wishes, and very recently an SA at CP said “the system doesn’t care about spending history when allocating, although there are still team members who review the decisions”. They also said the reason why the specs you can give on your wish are a lot more restricted than previously is because they’re trying to allocate bags better.
In our experience, purchase history and SA relationship don’t play a role in getting offers at CP. wishes can be fulfilled even with very limited spending, like a twilly, and no consistent SAs (our first wish was fulfilled within 2 weeks of setting it up and second wish was fulfilled within 4 months). I now shop at a different store where I don’t actually have an official wishlist per se, but still get offered bags which they think I might like. Who knows how the H system works!