According to Dennis..
*"Behr "Service" units were actually made in China and all the ones I have
seen had a different core design, round tubes instead of the oval tubes.
Similar to what was used in many early water cooled VWs.  This roundtube
core radiator has noticeably less cooling capacity especially when using
air conditioning. I have one in Fun Bus and it just doesn’t work well in
hot weather with AC."*

and I totally agree with this..

I had my radiator replaced on my tintop Syncro - before the temp needle
sits under the LED light, after replacing it with the round core it sits on
top of the led LED light. No overheating but annoying.