Your Program, Your Rules
You sprained your wrist playing basketball last weekend. The plan says Overhead Press but your wrist disagrees. Now what, throw out the whole program? Same story when the squat rack is taken, or when you're traveling and have nothing but dumbbells, or when your gym closes down and the new one doesn't have a cable machine.
A good program bends around these situations. You should be able to swap what needs swapping without the rest falling apart. Who doesn't like flexibility in their own workout schedule? Life imposes calendars on us all. The least we can ask for in a sweaty undertaking we signed up for is some wiggle room.
You've been running Flat Barbell Bench Press with a Heavy rep-scheme for weeks and it clicked. Why not try that same intensity on your Barbell Row? The exercise and the rep scheme are separate choices. Most setups fuse them without any good reason. If anything, experimenting with different stimulus profiles across exercises is how you figure out what works for YOUR body.
And swapping Barbell Row for Dumbbell, Machine or Cable Row? It's still a horizontal pull. The engine will ask you to test the new variant when it doesn't have enough data, then picks up right where you left off. Your growth within an exercise carries over to the entire movement pattern. A variant swap shouldn't feel like starting over.
How many days you train, which movement patterns go where — that should be yours to reshape without unraveling the rest. These are really just separate decisions.
This is how Jackked's programming works:
(1) Which movement patterns fill your week.
Your weekly template maps movement patterns to days — a 3-day Full Body might look like:
A 3-day Full Body template and its resulting Day 1 workout — Jump becomes Barbell Squat, Horizontal Pull becomes Barbell Row, Horizontal Push becomes Flat Barbell Bench Press.
(2) Which exercises execute those patterns.
Under each pattern, you pick which exercises fill that slot. Jump could be Barbell Squat, Front Squat, or Goblet Squat — switch whenever.
(3) How you train each one
Each exercise is independently paired with any rep scheme. Want Barbell Squat on Moderate and Front Squat on Heavy? Done.
Adjust any one of these without the other two flinching.

Swapping a custom exercise and rep scheme — the workout updates instantly.
BTW, you can create a custom exercise or a custom rep scheme and it plugs into the same system — the engine treats it no differently from the built-in library.