[16C] why are some commands entered before their arguments?

[cdmackay]

I keep getting tripped up on my DM16, when using FLOAT, WINDOW & CF, since they seem unique in that their arguments are entered directly after pressing the command key.

Whereas the related WSIZE, and of course most other commands, for example, takes its argument from the stack.

Is there any logical, or historical reason for this?

I can understand programming-only commands, e.g. LBL & GTO/GSB taking a suffix directly, rather than reading its arg from the stack, but for commands that are also used manually, like the three I mention in the first paragraph, it just seems confusing (to me).

Hmm, I suppose I need to include STO/RCL, too.

It would also seem to bar them from using calculated arguments, too (except for STO/RCL which can use indexed registers), which might have been useful for some of them?