Load Balancing Status on Volumes

Hi...I am currently using a mix of PS6000 and PS6100XS units.

I have only 1 storage pool, the Load balancing in Group config is enabled (tick)

I have approx 10 volumes.

Their RAID preference are all "automatic".

I noticed that some of the volumes have Load balancing status disabled while some were enabled. But almost all of them are using storage from all of the 4 EQL units (some uses only 2).

I cannot find any distinct pattern between how many EQL were used and if the Load Balancing is enabled or disabled.