From the Leedle Floral Co. 1914 Fall catalogue, page 34:
"Robert Heller - (Heller, 1911) (T.) Deep golden-yellow; a seedling from Perle des Jardins, deeper in color and stronger in growth. A constant summer bloomer, vigorous, thrifty and one of the most brilliant and beautifully formed yellow Roses yet introduced."
'Robert Heller' seems to be named after the nurseryman's son, and seems to be a counterpart for the rose 'Jeanette Heller' named for his daughter. 'Jeanette Heller' of course is the rose involved in the infamous 'W.R.Smith' mixup debacle, and wasn't bred by Heller. By best guess is that 'Robert Heller' is a rose bred by Hill and Heller had (or again thought he had) the naming rights. Perhaps there is another named yellow rose by Hill which is the same as 'Robert Heller'.