Are conception and implantation interchangeable? Trying to narrow down conception/ovulation dates. Help me better understand?

Not the same. Conception occurs when a sperm enters the egg. This usually occurs in the fallopian tube. After that, the fertilized egg begins to divide, creating more an more cells. During this time, the fallopian tube transports the embryo to the uterus. 5-6 days after conception, the nest of cells burrows into the uterine wall. This is implantation. Best wishes!