Okay, given the situation where you know that your data grids only have one row, there is a very nasty hack to go from the Quotation form into the row template instance. Your repeating panel is a container of instances of row template forms. In your case there’s only the one instance in each repeating panel. You can use:
self.repeating_panel_cxl.get_components()[0]
To get that instance, and then access components on that instance, e.g.:
self.repeating_panel_cxl.get_components()[0].coversums_cxl.text
This only works because you only have a single row in each data grid. It also puts code that is populating row template forms outside of the row template, so later on you’ll have trouble working out where that’s being set. But it should work.