Frost Blades

can we get some buff for non-trinity version?
full cold convert on raider extremely weak....

Skill description is unclear for me.
From my understanding on lvl 20 we have 400% DMG multiplayer... But it refers to phys base DMG only before conversion? or added cold DMG on claws or rings also is multiplayed?
There are several different opinions. I understand that 400% refers only to base damage (phys) and added cold DMG is just added but not multiplayed by 400%. I'm talking only about initial DMG multiplayed by skill not increased cold or phys DMG modificators.

What I mean is. Claws with 500 phys DMG will have more cold DMG than claws with lower phys DMG and flat cold DMG or not?

Like imperial claws for example. Let's assume claws have 2 prefixes and we have 100% conversion.

Increase phys DMG (first prefix) so base have lets assume 370 phys DMG
and
add 130 to cold DMG (second prefix).

Which calculation is correct assuming frostblades on lvl 20?

370 phys dmg x 400% + 130 flat cold= 1480 + 130 = 1610 cold after conversion
or
370 phys dmg x 400% + 130 x 400% = 1480 + 520 = 2000 cold DMG after conversion?