It is possible with a work-around.
Set the segments to be equal.
Convert Pattern to Segment Length.
Move the nodes so they are centred to the required tread and then set the post offset to the tread width (post will now be centred on the next treads).
Adjust the length of each panel so they - this bit is a bit of guess work as there is nothing to snap to and distances are on the stair rake and not horizontal as measured in plan.
This is all a bit long winded and not as simple as just setting independent distances for each post.
Barry.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10