Not all exercises are reps x lbs. Please add a blank box to notate more flexibly
Many many sports use body weight/other specific exercises that can't be described as reps x weight. An easy fix is to give trainers the ability to just add a blank box for unique sport notation. E.g, universal notation for hangboard training in climbing is 6x 7:3 (-10) (6 sets of 7 seconds hanging with 3 seconds rest with 10lbs taken off body weight). You are radically reducing your market by limiting functionality for gymnastics, boxing, rock climbing, swimming training and many other sports.