The voltages add when in series and the current adds when in parallel.
With 8 in series, the Array Voc is 37.2 x 8 = 297.6V
However, with 2 MPPTs, the strings are not in parallel, there are two separate Arrays. The Isc of each array is 13.6A.
On the white label, both MPPTs have Voc of 297.6...