Extension bug(?)

When I want to extend normalized curve (actually shorten it a bit) with parameter eg. "-0.3" extend component cant reparametrize it - it just cuts "0.3" units out of it.

Seems that is not a bug but it is intended to be like this - but how comfortable would it be to work like other components.

I managed (woo-hoo ;)) to solve it with multiplying curve lenght * parameter I want (just if somebody doesnt know how to replace reparametrizing)