I just completed a status match to EE and wanted to add a couple data points for anyone it might benefit.

Background:
I was Avis Preferred Plus with about 70 rentals last year, most were 1 or 2 days. Almost all were at a corporate contract rate. Company contract includes LDW so was always motivated to use Avis. In about 2 years of rentals, I earned enough points to redeem for five days in the midwest at a secondary airport.

Company also had a contract with Enterprise & their National brand, but until this year it did not include LDW. The renewal of that agreement does, so I decided to try matching... I was already Emerald Club and had rented four times in the past year from National when no car was available upon arrival or the only car was the reserved sixe (which cannot be higher than midsize by policy).

Process:
Googled 'national status match' to find that National has a dedicated website for this purpose. Selected my status with Avis, logged into national, and was prompted to upload proof. I logged into my Avis account but it lists me simply as Avis Preferred Plus, with no expiration date and no indication of which Preferred Plus level I was at. So I went to my points activity history (which also says Preferred Plus) and clicked "show more" until I had about six months of rental history displayed on the screen. I then printed that page to .pdf and uploaded that pdf. Clicked submit and 24 hiurs later recieved an email that my match was approved and I was now Exec Elite. The email also said it can take up to 7 business days to be reflected on my account.
I concluded a rental Tuesday, 4 days into the 7, and my account now shows EE and a free day. (4 credits from those previous rentals plus the one i just completed.)

YMMV