revision based on award of qualifying benefit

Hello. I’m a bit out of practice with this - does this rule still apply?
Claimant receiving SSP, claims but refused IS because income to high. Goes on to make successful PIP claim with SDP entitlement. Is it new IS claim or revision of old award - if advised within 1 month.
Thanks in advance

Does the period of PIP entitlement include the date on which the IS claim was made or on which it was decided?

Both claims were made on same day / within a week of each other and the JC+ were informed within a month of PIP decision.  I remember the ‘good old days’ asking for a revision based on an award of a qualifying benefit but as there has been some delay I am starting to doubt myself.