IRP office will need USDOT number of carrier responsible for safety in order to open new IRP account. DOT number doesnt have to be yours, but you'll need to provide lease agreement with carrier (even carrier is yourself). And they check status of it on. This mean if there is no insurance on it, that mean no IRP plates.
A lot do fleet avg. An OP could do a mock report to compare or question Carriers honesty. I’ve heard of some high charge backs that scream O/O subsidizing Carriers portion.
I still think Maybe they just want your miles and fuel receipts ( trip reports) so they can file Ifta.Having own plate is common enough but Ifta acct to lease onto another Carrier is very rare.First Ive ever heard of it.