"
so around 1pm I suspect the output would have been noticeably higher, but by then the batteries were no longer in bulk mode charging but absorption and the charging current dropped below the panel output as expected"
Exactly. To test these things you need to jump and dance all over the place. EG to get the afternoon AH haul to match the morning haul (as it should by bell curve) you have to hold the battery voltage down steady by running a load.
It is tempting to just take the morning haul and double it. Especially if the low sea is to the East and there are mountains and trees to the West.
