Question about fingering
When you change the number of fingers indeed, in first order,  the DC solution should not change. If it does then maybe something is wrong.

Some design kits might take edge effects into account so that a 10/1, fingers = 1 doesn't behave exactly the same as a 10/1, fingers = 2.

Note that in some design kits, if you start with a:

W/L = 10/1 transistor with fingers = 1

then change

fingers = 2

the transistor might become 2 x 10/1 = 20/1, so twice as wide!

In such a design kit you would need to enter:

W/L = 5/1 transistor with fingers = 2

and that would then give you the 10/1 transistor with fold = 2 so effectively two 5/1 transistors in parallel and a shared source (or drain).

Pro tip1: when placing a new transistor, make fingers something different from the default 1 unless it's a very small transistor. For example, when I need a 100/0.5 transistor I would make fingers = 5 or 10.

Pro tip2: create a layout cell view and instanciate a 10/1 transistor there. Then copy it so you have two. Now change fingers = 2 on the copy. Compare the layouts, is this what you expected?