Drainage on Flat Roof Deck

On your show, you mentioned a product that will help resurface an uneven deck. The deck is upper level & waterproofed so the porch below stays dry.  So in a sense, this a flat roofing question.

I have a sloped deck that drains to a gutter on the lower side.  The coating is AMES Safe-T-Deck elastic paint with granules.  Thing is, the flashing between the gutter and deck creates a lip that causes water to pool rather than drain.  Over time, the pooling water drys out and deposits hard to clean dirt.   I want to fill in this area with a thin coat of material to result in a continuous slope to the gutter.  Once that is done, I can recoat the deck.

What is a good way to do this?  

Thank you.

Warren