correct, paste is ‘additive’ i.e. it takes what is in the destination and adds the new step onto to it.
it doesn’t replace (as it would do on a computer/daw)
this is no real issue, for a replace, just delete first i.e. 2nd+DEL , 2nd+PASTE
and once you know its additive, this actually is fun e.g. try it with CC modulation, you can kind of overlay two modulation patterns… or with notes, have two note patterns and create a 3rd which is a combo.
also remember you can copy patterns over multiple pages by zooming out when you do the copy - when you paste its needed it will cross pages.
(sorry im using patterns here loosely as a group of notes/cc… not the ‘squarp pattern’)