Savero Tyres

Hi I have been running Savero AT's on my 2006 Hilux, they have done 30k on our trip around oz. I took them off for 3 years and had them put back on 6 months ago.
There is plenty of tread left, but I am not too sure about their handling in certain conditions. I sometimes feel that in the wet they slip a bit more then they should.
Also when you merge from 1 lane to another and the road has some lumps and bumps it feels that the tyre rolls sideways (I mean the tyre wall rolls over).
It might by just me or the actual roads, but I thought I would ask other Savero users.

Thanks
Wato