Alternates next to base glyph? Numerals not behaving the same

[lettersfromswe]

Why is not the numerals behaving in a similar way when this checkbox is checked?

If there is a good reason for this; is there a way to “hack” glyphs to have numerals displayed next to base glyphs also?

[GeorgSeifert]

The numbers are treated a bit different as the different number sets (.tf, .osf …) need to be separate, otherwise it would be really confusing.

[lettersfromswe]

Yes, but I was thinking of five.ss01 for instance. It feels odd that it sits before the five.tf instead of the five IMHO.