You didn't mention which side of the tires are cupping.
If it is the outer edges on both tires - Your towed in too much.
If it is the inner edges of both tires - your towed out too much and the tires are scrubbing against each other as you drive.
I would suspect this shop is trying to muster up repair work based on their
false diagnosis of the belt and oil.
Ask them for a print out of the final alignmernt where you can verify the readings
that are within specified ranges.
If the give you a hard time ....Run dont walk from their facility.....

these r so so beautiful i love the reflexes and the cheap ones i only recommend on ricers

Thanks for all these tips. I haven't even looked very closely at the tires to see where they're cupping. I did a bounce test on the corners of my car but it stabilizes immediately, it feels really solid.

I took a look at the belt myself, and boy-howdy, it really does have a bunch of cracks in it! (Still, I think even a belt with cracks will last a long time, but I'll prolly replace it anyway.)

So I think I'll get a professional inspection of the suspension and find out if it'* really the struts. I think I can probably handle replacing them myself if I need to, I've pulled an engine before, and it looks like I can rent those spring compressors. If I do the job, I'll check out the strut mounting plates too.

I examined the treads, and they're just the smallest bit slanted so that their leading edge is a little higher than their trailing edge, but it'* very minor, and the car is running very smooth and tracks perfectly straight after the alignment. I'm tempted to just forget the whole thing. I'm beginning to think my struts are just fine!

If you bounce the car and the body comes up and stops you dont need struts.
I've heard of these factory struts lasting the life of the car.
Both my Bonnes have originals and perform like new.
Sounds like your right on track to whats going on.
The reason I stay out of repair shops is they are allways pushing a uneeded repair
to make a quick buck.
Can't tell you how many times they tried this on me.
Although our local Buick dealer has never done or tried this.

I agree with you there, my dealer (while expensive) has been honest with me 99% of the time. (Sometimes they get a new guy who pushes stuff I know I don't need, like when his 10-point inspection said I needed new wiper blades, when my blades were EXACTLY one-day old, and the old-standby "cracked serpentine belt" which they'd replaced the month before; -that'* when you KNOW they're jockin' you.) But I know my dealer has saved me money by knowing the GM cars up-front, where other shops guess and shotgun things to try to fix them, my dealer is usually already familiar with the minor bugs in myBonnie.

I think I'm gonna sit tight, if I do a bounce test and let go, the car comes up and stops immediately, it doesn't even bounce once. Reading through this forum I saw where people replaced their stabilizer links. I looked at mine, they're the old fat original ones, but I don't even see a nut on top of them. Is there supposed to be a nut on top of them? I can take a picture and post if that will help.