As for your edit…that is not deferred revenue. The only deferred revenue that RM could book is if someone paid for a truck but RM had not yet delivered.
Same for Mullen…
They could only book deferred revenue if they got payment for a Vehicle they had not yet delivered. That is not the case.
The conditions you are referring to are those required to return the vehicle for a refund…and that has zero to do with “deferred revenue”.