double the number is wwwwaaayyyy too much! Never do such a flight!
52 is not the double of 33. And wide body don't need necessarily need to have a higher ACN than a small one. They have more wheels!
If your "friendly" ops office really insist, let them give you the written approval. As an airline you always need also a letter from the airport you want to operate, i.e. you need an approval. You simply cannot go to any place you want. If you receive it, then everything is fine!
It's correct when you say that it's not only a question of the RWY but all apron surfaces.
I'm pretty sure that your board documents say which class of aircraft you are, maybe even the PCN number is listed. With that in hand you should easily prove that you are allowed to fly - if the ACN match the PCN...
Maybe CFU just has some very remote areas with a low PCN and to protect themselves, they give the PCN for every surface as the number 33? Why not drop in the CP office and ask him? He wont bite (well, sometimes...)
Good luck,
Dani