It sounds like you're talking about Make-X. Which was introduced in 2005 for RS2.
There was nothing like this in RSC.
RSCR does however have a feature called batching
The higher level you are in the skill you are training, more batches you can do.
BaseLevel/10 = Number of batched actions that you can perform.
Platinum subscribers get 1.7x more batched actions, rounded down to the nearest integer.
The number of actions that you can do is updated every 10th level (10, 20, etc.).