there is always many ways.
One of them:
create new address, name it,
leader: G15 H, expresion: fixture offset variable (find it throgh debug or in variable browser)
set modal, or non modal
Put this address as a block in some section, start operation initial+first move for example.
If you are new to PB watch all videos about PB on this page and sme on youtube.
To whom is may concern:
It might be worth noting that the variable $mom_work_coordinate_number (as used by the G-Work Coordinate Selection word) generated an error message.
The variable $mom_fixture_offset_value (as used by the G - MCS Fixture Offset word) worked great.