That shouldn't cause to much trouble as long as the cap that's in there is not to heavy on the plus side of the tolerance. Where you run into trouble is if that one goes bad and someone else comes along without the proper info that you have and all they see is a 50uf capacitor is bad but all they have is a 55 or 60uf and they say to themselves, this is close enough and it turns out to be a cheap Mexican cap that fails in a year, now you don't trust the last guy so you call someone else and all they have is a 60 or 65uf,,,,,,, you see where this is going? It is always best to keep the correct size if possible but in your case you know whats in there and what it takes, it should be fine. a 45 uf +- 10% could read 49.5 but keep in mind a 50uf could read high as well and be within it's own specs
