Hello @Stefan Schippers, @Tim Edwards, I would like to know if this is a bug in xschem or magic, where with the same dimensions the value is not the same.

The pwell resistance is 3.82 kOhms/square, so your resistor is (27.44 / 2.65) = ~10.355 squares * 3.82 = 39.6 kOhms. Magic's device generator has the wrong value for the pwell resistance. Xschem is using 3.816 kOhms/square, but you've specified "mult = 5" which indicates that the devices are in parallel, so the total value is 39.6 / 5 = 7.9 kOhms, which is what is displayed. I will correct the reported resistance in magic. Note that the device model uses L and W; the reported value in both xschem and magic is for design reference only, as the device will simulate according to the physical dimensions of length and width (and M, for parallel combination). Once corrected, magic will still display a slightly higher number than xschem, because magic adds in the terminal resistance. That just means that magic's displayed value is slightly closer to the actual simulated value. But there are a lot of factors that go into the modeled resistor's value, so both xschem and magic will display a "more or less" accurate value, but you should always depend on the simulation to fine-tune the resistor value to get the correct frequency response from your circuit. The same thing applies for the capacitors---the actual simulation value will account for fringing cap and substrate cap that aren't present in the displayed value in magic and xschem.

Does this not affect when making LVS?

LVS matches connectivity and geometrical dimensions. So

W

and

L

(and multiplicity if set) are checked between schematic and layout, not the value, displayed only as an 'approximated nominal value'' (with some missing components like fringing / perimeter) for designer convenience.