My program requires that I do sets that differ in weight by 5 lbs. The machines at my gym only go in 10 lb increments. For example, if I am supposed to do 15 @ 50lbs and 10 @ 45lbs should I go down to 40 lbs or stay at 50 lbs?

This is a common problem that many equipment manufacturers have not figured out how to solve yet! The weight plates that come on the machines are always roughly 10 pounds. The 10-pound size seems to be the industry standard. You might want to ask if your gym has a 5-pound “increment plate” that could be fitted to the existing weight stack to provide for 5-pound weight changes. Most high quality equipment manufacturers will have this 5-pound increment plate. Now, if your gym does not carry a line of equipment that offers these special plates you will have to do the following. Just round the weight up or down but always be consistent in what you do. It doesn’t really matter what direction you decide to round because rounding up or down will eventually lead to doing a set with the same weight as the previous set even though the repetitions have changed. Confusing, I know! Just be consistent and you will be fine!