The heads of quite a few 4.5 and 5.0mm screws will tend to pull through an 8mm hole in softwood (e.g. framing) - that just doesn't happen when you have a 7mm or smaller hole. 6.0mm screws are OK with the 8mm hole, but then the heads on those are pretty big. Screw head sizes vary a lot and it makes sense for me to not have to adjust plug sizes, etc for every task I undertake
There is no way round it other than to use 6.0mm screws and given the volume of screws we put in it simply isn't viable to change our approach. TBH I've never come across a joinery contractor or shop fitting contractor who used 8mm plugs, either
