A320 ground single pack ops
 

Does somebody, know why it's best to turn PACK 2 off over PACK 1 during turnaround?
From my point of view (because of the volume affected to cool/heat) turning the PACK 1 off would be a better solution..
Any advise?

As I understand just so that it is a bit easier on the people loading cargo which happen to be on the starboard side

Some reasons I can think of.

1. If your keen on doing SETI (single engine taxi in), then it's better to turn off PACK2 after Landing. After cool down period you can shut off ENG2 and finish your taxi, but still have fresh air supplied to the cabin via Eng1->Pack1.
Otherwise you would have to open the cross-bleed to supply Pack2 with ENG1-Bleed.

2. as maybe 1% of my captains perform SETI, I usually just alternate between packs. That allows equal distribution of wear.
That is pack 1 for home base , pack 2 for away from home base

3. Noise for the loading crew can be a factor.

4. Business Class PAX should get more air. (Pack1 supplies more to forward cabin, Pack2 more aft)

Because you can simply leave pack 2 off and SETO on PACK 1... Easier SOP!

This is what we do. Taxi in with pack 2 off (SE taxi in) and SE taxi out with pack 1 off. Pack 2 supplied via x-bleed