WLP550/3522 has much more complexity than WLP545, and lower attenuation.
@VikeMan is correct; these are on different wings of the genomic charts, not related at all, even though some of the characteristics are similar.
WLP550/3522 average apparent attenuation is approximately 85-87%. Even though it is technically not diastaticus... it might as well be. That's pretty high attenuation. It produces complex notes of pepper, clove, banana, pineapple, and other Belgiany stuff. It can be and has been used successfully in saison styles.
WLP545/3711/Belle has extremely high attenuation averaging closer to 95%. Commonly the FG will be 1.002 with this strain. This family of saison yeasts (the three are not exactly the same but extremely similar) has milder characteristics of pepper and lemon, much less expressive than many other Belgian yeasts. Some would say it's relatively tame and boring, although I myself like it a lot.
For an Achouffe clone, I'd reach for WLP550/3522 in a heartbeat. Expect high attenuation and dry finish, and wonderful flavors.
That makes sense. IIRC
@dmtaylor has on his yeast spreadsheet that WLP545 could perhaps be the strain that Lallemand sells as Farmhouse, their non-diastaticus saison strain.
Thanks for the mention. However, I don't currently have WLP545 listed alongside Farmhouse, as the attenuation of Farmhouse is much lower at about 83-84% average. Maybe you have an older copy of my sheet. I'm thinking Farmhouse is likely more akin to WLP570. But of course this is only a wild-ass guess, too. WLP545 is almost identical to their Belle strain though.