Singleplayer and MP are balanced seperately. However...
I don't see patch notes separating adjustments yet but perhaps that will come. Spear nerfs continue everywhere for example (reduced headshot damage, reduced stun). Those were only implemented due to calls from skirmish/deathmatch players who still consider spears to be OP in grounded combat. Any changes to SP A.I. cross over as well, with Captain's mode being both PVE and PVP it is more susceptible to all these changes greatly affecting its balance.