I think the reality is, that for most of the “recent” Tiffin gassers, until you see the weight stickers on a specific coach, it’s a guess at best to what weight rating a model may have.
I just quickly ran through the online brochure archive back to 2013, and this is what I found and some commentary on the 31/32SA, 34PA, and 36LA.
As I’ve noted before, keep in mind the UVW of the raw 24k GVWR / 30k GCWR chassis from Ford weighs ~500#s more than the same wheelbase 22k GVWR / 26k GCWR so it nets you ~1,500#s more carry capacity.
But, with the 24k/30k chassis you get to use the entire 5k hitch rating without exceeding the GCWR vs. having to manage your actual GVW to tow 4k-5k on the 22k/26k chassis. In reality, with a 5k hitch, the effective GCWR is really 29k.....
Going from the 24k/30k to the 26k/30k only changes the rear springs from 15,500#s on a 17,500# rear axle to 17,500# springs on the exact same 17,500# rear axle, and the UVW if the raw chassis in only about 10 (yes, ten)# different between the two. Going to the 26k/30k you do have to manage your actual GVW if you want to tow 4K-5k and stay under the GCWR.
31SA was always standard on the 22k GVWR chassis. However, you could request a 24k GVWR chassis build (as I did, weight sticker below
), but it wasn’t a published option. I have consistent weighed ~22,600# fully loaded for extended travel including full fresh water. F/R weight distribution is excellent, and my 4 corner weight was excellent L/R on the front and very good L/R on the rear.
32SA varies by year as to what the “standard chassis” was; some years show 22k GVWR, others show 24k GVWR for 2019 & 2020 they actually show both chassis options in the brochure. In any case, published or not, you could get a 24k chassis build if you asked.
My guesstimate is that a similarly equipped / same chassis rating 32SA has an UVW ~350#s more than a 31SA, with all that weight behind the rear axle for the 1ft added to the bedroom.
34PA was originally (a late 2016 model year release) standard on the 24k GVWR and I’ll simply assume you could have requested a 26k build. From 2017 on, the brochures show the 26k as standard.
36LA has always shown the 24k GVWR chassis as standard, but there are some out there on a 26k but never shown as an option.