Do you know why your doctor specified the added proprionate?
The cypionate will provide a more stable longer lasting base as it is a longer lasting ester.
Proprionate has a shorter half life, hence more rapid uptake, peak and trough after dosing. Commonly on TRT, guys are using it daily to mimic diurnal hormone rhythm. Taken alone, not combined with cyp it is generally taken ED or EOD. I don't why added prop in the formula would help if dosage was less frequent.
Speculating here, I'd anticipate with E3D, you'll have two different bumps in blood T level on a three day repeat. Maybe the idea is that the prop kicks in first then cyp provides a secondary peak before next dosage over 3 day period, while the longer cyp half life carries your baseline/trough along at a high enough level.