Delaying Signal Processing

I have tried using the "&delay=x" parameter to batch several trading signals into a single e-mail to subscribers but it seems to have no effect.

For example, if I wish to issue three trading instructions I add &delay=180 (ie, delay 3 minutes) to the first 2 then &delay=10 to the final one which should expire well before the previuous two thereby triggering (according to my understanding of the documentation) a single e-mail containing all three. Is this correct?

Has anybody else got this to work?