Frequency of injection is not only about blood levels, but also about the amount of oil. 150mg of each, equals 3cc eod. It would be a pain in the ass to be shooting 3cc in delts or lats, considering that you are using at least 4 diff spots to give enough rest for the other ones.
If you run 3 prop compounds, EOD becomes almost impossible. Depends also on the concentration but 90% of products come on 100mg/ml. 3 diff. prop esters EOD would be 4.5cc at 150mg each EOD.
If you have 4 diff body parts to switch, equals 8 different spots to pin. Doing it ED is much easier that way. Gives enough rest to the same spot, and you are shooting only 1.5cc ED considering 2 compounds. Using 3, would be 2.25cc. ED. Still good.