Amoretti has a number of different formats.
Was this an extract, or one of those syrup/concentrate/paste-like tubs? Or a puree?
Different flavors in different formats are obviously going to be different, but I played a lot with a sample pack I got from them, and in general 3 of the ~6oz (off memory here) sample tins of the concentrate syrups was good for 10 gals. I'd either add at flameout or when packaging.
I wasn't wild about the actual extracts. Dosing didn't seem to scale. I think getting the extract evenly dispersed was difficult. So the final product would either be too strong or too weak, and then swing the other way.
Their fruit flavoring purees I never bothered with. Every one tasted and smelled like chemical toilet.