That's a neat trick. Of course some of the number weirdness comes from that fact that standard kg plates are translated approximately into lbs in the US. So you

That's a neat trick. Of course some of the number weirdness comes from that fact that standard kg plates are translated approximately into lbs in the US. So your 45lb plate is actually a 20kg plate and your 25lb plate is based on a 10kg plate. Although 10kg is actually around 22lb. I'm not sure whether the same colour plates genuinely weigh slightly differently in the US vs the rest of the world.