The top is supposed to be wider than the bottom. Sounds like you may not have enough weight to make the axle straighten out. Or like mentioned check the toe in.
You can get a #4400 axle too. No need for #5200. If you're TT doesn't weigh enough to straighten a #3500 then it sure won't with a #4400-$5200 axle.
Here's a quote from someone else with #4400 axles.
Just got off the phone with the parts guy at Lippert. I was trying to find out what #'s I needed for the bearings and seals for the 4400lb axles I have. Couldn't find any part #'s for 4400lb axles on the Lippert site so I called them. The Axles are rated at 4400lbs, with 10" hubs and have 3500lb axle bearings on them. Same bearing #'s (L68149, L44649) you would use if your buying bearings for any 3500lb axle. Seems weird to me, but just wondering if it's normal to have bearings that fit 3500lb axles on 4400lb axles. I'm not an engineer, so I don't know if the bearings are capable of carrying more if the axle is built to higher standards or what. Any engineers out there?
One thing to consider if you haven't already is that normally 3500 axles are 2-3/8" OD and 4400and up are 3" OD. You'll have to change you U-bolts to 3" and also buy new spring plates.
Also need to make sure the spindle length will work. But it looks like you could get a #4400 axle and still use the #3500 hubs and bearings as long as the spindle length is good.
I would take it to an alignment shop 1st. Not the dealer. They're usually clueless on bent axle issues. Plus the alignment shop may have some suggestions to save you some money.