O.K. Using your numbers 22,700/70,000. You only got about 33% of the Warranted 70,000. So, you would be entitled to a 67% credit from the price you paid for the tires. DT does charge for balancing and mounting the new tires (about $100). Assume you paid $800 for the worn- out tires, the prorate credit would be 800 x 67% or $536. I stay in the Michelin brand of replacement tires and apply the credit. Say the replacement Michelins now cost $900. Then, $900 less your prorated credit of $536= $364 + the $100 install = $464 for a new set of Michelins. Hope this helps. I'm a 3/32 guy and gettin' the $536 prorate. Ymmv.I think I can pay less than a prorate by shopping for a deal and getting DT to match/beat it.
With a prorate you start with full price then subtract for the adjustment.
The prorate - if I understand it correctly requires you to wear down all the tires to 2 or 3/32 - I will never get down past 4/32 before I am buying new tires. My safety is more important than a few $$.
If this is incorrect please set me straight -
IIRC - I had about 15K on my Michelin Defender LTX they start at 12/32 they were down to 6/32 and had a 70K mile rating.
I ended up at 22,700 miles and they were 4/32 - NO WAY they go to 70K
So 6 out of 10 usable gone in 15K - DT said there was nothing they could do until I was 2 or 3 32 and that was in so many years 5 or 6 I can't recall.
Proration doesn't look like an option I could ever use.