We received a similar bit of info from the airline i work for too.
They had a little more information on it though. Turns out that the quadrantal format as entered into the Boeing FMS, is transmitted via ADS correctly.
However on our Airbuses we are required to punch in all the LATs and LONGs manually as when we use the quadrantal format, it isn't transmitted as a properly formatted ADS message (according to the ARINC spec). Causes some confusion on the ground equipment i believe.