But for the benefit of others, "punching in," by whatever name, may be accomplished on MPad, or pretty close.
Methods vary, but one way is to "mix down" everything to an mp3, or wav or whatever, then import it as a "clip."
Set up a separate track to record the fix. Place the cursor at a point close enough to the offending material to avoid redoing the entire track, but far enough away to give everyone time to get in sync with the mix-down. Then record the fix.
Play everything back. The timing will (hopefully) be right. But of course, you'll have BOTH good and bad playing back at the same time, where they over-lap. Use fade points to kill output of the bad just before it begins, and just after it ends. As Duke Ellington said, "If it sounds good, it IS good." When you're happy with the playback, mix down everything to a new file.
Hope that helps.