After changing seating config of the plane Dash 8-300 from 52 seats to 48 seats of same Standard type of seat with added seat pitch, and the number of flight attendants changed from 2 required + 0 extra to 1 required + 1 extra, the turnover time which was previously scheduled just right now become up to 4 minutes too less for some flights.
And checking the Turnaround activities reveal that the time take longest to complete during affected turnaround is baggage/cargo loading/unloading.
I do not understand why removing seats cause loading/unloading baggages take more times?
Because with fewer seats, and your MTOW being a given, you can likely load more cargo weight/fill up more physical space of the plane up with cargo. The same happen with for instance a 32Q Light. Fewer seats generally equals more cargo in case of MTOW restricted aircraft.