Which panels?
Does the data sheet give NOCT power? Can you find them on CEC website, and what PTC power is listed for them there?
Rated STC watts are under conditions of 1 full sun and 25 degree C cell temperature.
Under realistic conditions, they typically produced 70% to 85% of that, but occasionally conditions are ideal and they may hit 100%.
Off season, the sun is filtered through longer atmosphere path. Summer, they are at elevated temperature. As they get older, they produce less.
It does sound like you should have gotten more than 67%.
Was battery near full at that time? Could have charged most of the way in the morning, and battery was accepting less at that point.
Data sheet page 47, looks like 24V battery and relatively low PV voltage should be 98% efficient and 600W
(Good they provide these curves, not seen for many brands.)
What voltage are the panels putting out when operating at maximum power point in hot weather?
Try two in series (so long as Voc would not be too high, nominal and adjusted for freezing.)
If battery is at elevated charging voltage, in hot weather Vmp could be lower, and SCC needs some headroom.
Page 41 it says battery voltage +2V, doesn't need much. If the specs are done well, that would even be at full current.
But try higher PV voltage (which should only decrease efficiency 1%.)
If that doesn't help, go back to lower voltage, because 2% loss is 2/3 the temperature rise of 3% loss, better for reliability.