Yes, these twinned holes are for verifying the quality of the original drill program, as I see it. If you drill to 150m and your core shows the minerals only present to 120m what would drilling to 150m actually prove? It would prove to be a waste of money.
Also if you drill to just 80m you can prove the integrity of the prior drilling if the grades are perfectly consistent throughout.
The point is not to replace the cores you have, but to verify that you are not seeing smears or other artifacts in the old cores.
SRSR was not present when the old cores were drilled, so verification is wise.