flat lawn, best slope to have?

[Mike13]

I have a rectangular bit of lawn in front of a patio, and I am putting in a step on the edge away from the patio, that goes right up to the house.
It is 3300mm from patio to lawn edge of step.
The most likely level for the step is about 40mm below the edge of patio next to lawn.

Should I try to raise or lower the step by adjusting mortar thickness in the course of bricks that will support the edge of step away from lawn?
Does it even matter with that slight slope? Soil is fairly free draining where I live.

 

[Pat ex]

I'd suggest a plan and a cross section of your situation would help, or a photo, because it's difficult to visualise your scenario.
Why can't you leave the 40mm as the step down? What are you stepping down onto? Why does it need any mortar adjustment to the step down? Is it just the edge of the lawn collapsing that concerns you?

 

[Mike13]

The lawn slowly droops between the patio and the step, 40mm has the step flush at the top.

It was concerns about heavy rain letting rain puddle back onto the patio