Hi @slisajacobson welcome!

Do you already have a sample code snippet that you can share? Or give an example using the sample data?

I don't have a particular snippet - apologies. And was not describing it very accurately.

I should be more specific that I'm looking at premium on-level and development. If I use the ParallelogramOLF method to on-level premium it will do so to the development I specify when I construct the triangle.

There is a case where I want to develop the premium to a different date (using DevelopmentConstant, which also uses the development specified in the triangle). I think of the on-level and development dates as being on two different axes for the triangle. This may be outside the intended scope, but was curious if anyone has looked at best ways to handle that? Right now I'm just overwriting the development date and then storing the on-level date when I write the triangle back to a table.

There could be an analogous question on loss trend vs development, where TrendConstant will use the development date as the valuation date, and one might want to have a different development date for loss development (i.e., on development age and not valuation date?)

This is not a problem at all with chainladder because it is doing what it says it is doing, but I was curious if/how others have handled?

Thanks! It's a great package.