-em suffix is not productive as -im suffix. When you hear -im suffix for the first time it sounds quite natural. You can figure out what it means easily. -em suffix is not so productive at all.

you cannot many -em derivatives.
tut-am kur-am dön-em etc.

Seems like they tried this on biç- verb. But it is not widely accepted.

Seems like biçem is more used in IT field when you google.

By the way "style" word has entered Turkish as "stil" and "biçem" is offered for it.