Current density values and trace widths are related to acceptable conductor overtemperature, they are no magic numbers.
Heat dissipation mechanisms of PCB traces and inductor windings are completely different. You can't compare them. Trace width calculators give at least a reasonable estimation. The overall PCB heating, also considering other parts and acceptable voltage drop may require a correction of trace widths.
I would also calculate the total trace power disspation and individual voltage drops and check if it's acceptable. As a rule of thumb, 1 oz (35 µm) copper has a sheet resistance of 0.5 mohm. The value is the resistance of a square conductor element, e.g. a 400 mil wide, 4 inch long trace has a resistance of 5 mohms.