I use .inp files for the same reason. I didn't realise that you could do this until recently when playing back one of the .inps from this site on Lode runner IV and suddenly realised I could continue playing.(posted 9894 days ago)Now I use .inp's to play through to a certain level, great when you can whizz through the game at 1000% speed. Saves hours of needlessly playing the same areas again , when you know that you would compete them in the same way everytime.
Of course when it comes to recording a new .inp file fro the high scores you have to play the whole thing but it helps with practising the difficult levels.