Drop rate increase mechanic

I'd like to know if any bonus to drop rate we get from other sources (pets, scrolls etc) is additive or multiplicative.
If for instance I had 5 tier 4 arctic foxes (+20%) max knowledge buff (+20%) Kamasylve's blessing (+20%) and used an item scroll (+100%)
The server added on drop rate is +900% (so basically ten fold)
Will my new drop rate be +1060% related to the base?
or will I get +160% of the servers increased drop rate? (for a total of +2500% or 26 fold)

getting +160% is a pretty long task though, and item scrolls only last for an hour, It'd be a shame if these buffs combined (+1060%) gave less than a loot drop weekend (+1100%)

right now I only have 1 arctic fox and just tier 3 for now, +3% compared to +900% is negligible so I'm wondering if the calculations are multiplicative making the drop rate worth chasing haha.

 

You will get 1060%, also idk if you can stack foxes.

 

you can stack the foxes since the +1/2/3/4% drop rate isn't a special, and it doesn't say 'this buff doesn't stack' like the otter fishing one for example.
Are you sure about that? I heard Kolka gave an official statement on how drop rate works but I'm yet to find it hence I asked in the forums ( would appreciate links : D )