I ordered a similar kit from a China based company. 2x 300w panels with HLG-320h-48B’s. Mine only drew about 260w when I first hooked them up. I contacted the company and they were no help.
Even though they’re labeled as B type, they have the current adjust pot built in. (Like they’re actually AB type…is there supposed to be a difference in the label?) I opened them up to 320w each and all is well. Hope this helps someone.