In this sticky post , the guidline for counting repetitions of iM elements reads "For elements which alternate directions, eg) RC/PE4>iM, complete the total rep count on each side (unless explicitly indicated, as in sPL/PE2>iM). That is, left + right = one complete repetition."
That would indicate that mastery at the new SL/PE1 involves touching each side 30 times:
left + right, 1
left + right, 2
...
left + right, 30
However, you posted "15r per side is brutal enough" indicating you intended each touch to be considered a rep:
left, 1
right, 2
left, 3
right, 4
...
right, 30.
So this change is simply for the sake of being consistent in your instructions; it doesn't change the amount of work required for mastery!
Thank you,
wmarler