However if your batteries were at 48V and Vmp 68V then there's 80-odd watts per panel you're throwing away, and it's a whole different ballgame.
We sometimes have that situation early in the morning. After I read your post I got curious. Our bank is about 49.4 right now. I shut off the disconnect and checked the Voc of those panels and it is 75.1V. I think their "official" Voc is 36.7 per panel, but it's a little cool out this morning - only 12° F.
Vmp is the important parameter here, far more so than Voc.
The greater the difference between your battery voltage, and Vmp, the more benefit your MPPT will make.
Maybe I should hook the controller up as long as I already got it. It's a strange thing because the east panels come up to full power really fast in the morning. The sun is barely above the horizon right now and the east/west panels are producing 197 watts already, or 19.7 % of the installed capacity.
At the same time the south facing array is producing 88 watts, or only 2.3% of the installed capacity.
The sun is just slight north of due east when it comes up this time of year.
Assuming they're mounted substantially vertically I can well believe it.
If the sun was as little as 12 degrees south-of-east and your south-facing arrays were facing perfectly south, you would get a mere 2.4% of the available light striking them due to the cosine error.
The solar installer where I bought the panels said we wouldn't get good power production by putting them east and west. In the winter, I agree, they wouldn't work good. But this time of year it is working fine.
The installer either doesn't know what he's talking about, or doesn't understand what you're doing. (Either way, don't ask his advice on stuff he clearly doesn't get!)
I posted this elsewhere, but I'll put it here too because it makes the point so clearly...
We're just on the winter side of the equinox here now, so this is FAR from the summer "WOW!" state:
The red line is a tracking array, facing 30 degrees above east at sunrise.
The yellow line is an identical array facing north (your south) at the optimum angle for this time of year.
Just look at the difference in the first couple of hours of sun...