it depends on, if you already upgraded the vehicles with the coupon to sell on market, you have to wait about 90days to sell them.
if you keep the upgrade coupons (both) then the next premium BP without the extra 15 levels you have it.
Only reason i do it for the 125 lvl is to get the next BP for free and who knows when a previous BP vehicle will be broken after an update, i tend to buy an extra from each BP/event vehicle in the past 3 years to sell them when it becomes broken and can sell it for a lot