Strength fluxuations are a natural part of training and aren’t necessarily a sign that you’re not getting stronger or something is wrong with your training program. As long as there remains an upward trend over time, you’re good! Stress, sleep schedule, recovery time, and how much you’re eating can all effect how strong - or not - you are on any given day. Disrupted training, like going on vacation or being sick, can also cause a dip in strength, but these setbacks are usually minor and getting back to your pre-break levels happens relatively quickly. The changes in strength can often be small numbers, too small to be noticed when the minimum weight you add is at least 5 pounds. The use of smaller fractional plates help make the flucuations in strength more clear.