I see no harm at all with using that much PEA at one time. I have used a 20oz bottle of the large vehicle fuel system cleaner(same exact stuff just bigger bottle as regane) and its rated for 35 gallon tanks. My little daytona has only a 14 gallon tank and it didnt mind it.
Possibly newer vehicles with more sensors could be negatively impacted at the higher add levels but I really doubt it. Consumer products are made to be as "idiot proof" as they can be.
Like Blue99 said, 3+ bottles in a tank that size MAY cause a problem though :lol: