If I don't mistake basically each shell is multiplied to make a full reload time, in stoodakiss' case it's 3.6 full reload time with 14 mag and 0.4 shell reload... It should be 0.4 * 14 = 5.2 but it says 3.6...
Check out stoodakiss video for clarity at 0:30 and 2:19... I think pump shotguns did get a reload buff after all.

