Proper inlet/outlet routing on Baseray style cast iron baseboard

dhowes2112

My local boiler/HVAC contractor recently installed for me a single 4' section of Baseray style cast iron baseboard (using 1/2 pex). This was done for some kitchen remodeling and replaced a traditional upright cast iron radiator from 1914. The system is a pumped gravity conversion. Overall, the house heats very evenly with the exception of this baseboard. ONLY the very top of it gets warm, the mid-section/bottom is lukewarm or even cool to the touch when system is heating. I pulled the end caps and see that he plumbed the inlet AND outlet using the top "taps" at each end. Seems like the heated water just pushes across the top to opposite end and doesn't flow through the unit properly. Shouldn't it be bottom/bottom (or top/bottom) for the inlet and outlet to achieve more consistent flow and heating?