I don't think he is confusing anything. If you use company resources, that company can claim it was a work for hire and claim copyright ownership just like they do for the work they pay you to do whether they commissioned it or not.
Sure, you can fight it in court, possibly win, but while costing you crap tons of money while being unemployed at the same time. Oh you think you would still be employed after being fired for misusing or theft of company resources and actively in a court battle over who owns the rights to the product of that misuse or theft? I doubt it but hey, maybe you don't need to work which begs the question of why not just quit and make the apps and not worry about it altogether.
For all practical purposes, anything you create at work, or relating to your work, will in all likelihood be claimed by your employer and there isn't much of anything that can be done about it.