Day 3 vs day 5 transfer

We will be starting our third round of ivf in a few weeks. First round we did in April, had 11 eggs, only 5 were mature and fertilized. Only 1 made it to day 5 for transfer which we transferred. We did end up pregnant but miscarried a week after they confirmed our pregnancy. We just did a second round in July. Had 6 eggs, 4 were mature. We fertilized doing icsi this time and only 2 fertilized. None of the eggs made it to transfer this time. We are going to start round three the middle/end of September but now they want to do day 3 transfer with 2 embryos vs the plan of 1 embryo day 5. Has anyone had their plan changed this way before? Has anyone had more success with day 3 vs day 5?