Well, let‘s take a look at your situation. What level are your athletes or clients at? New athletes or clients probably would not benefit from percentages as much as more advanced clients, as they need to learn how to perform the lift correctly first and foremost. Second, a new client will adapt to the exercise so fast that by the next time you perform the exercise, their 1 rep max may be out of date and thus their percentages would be incorrect (if they used to bench 100lbs, but after 2 workouts they can bench 110lbs, that 60% you have them working out as now too low to cause the adaptation you are looking for).
Experienced Excel users will appreciate that textboxes default to having a border and white background. That‘s because they are often used to add comments or guidance to a user and so have to stand out. Otherwise a user would be foolish not to type words directly into the spreadsheet‘s cells. As equations can only be created in textboxes, the default settings are somewhat different; there is no border and no fill.