This might seem like a stupid question but I use conventional Mobile 5w20 5000 in my '06 & '16 minivans. Instead of using Mobile 1 Syn. I'm going to use Pensoil platinum 5w20 syn. in my '17 Big Horn 5.7. My question can I mix a qt. of 5w20 Mobile Syn. in my '06 to get rid of the bottle? ftd