No, there are other methods. The favorite one is finding a different seed, XD. If 503 is your calibrated delay and you absolutely want to hit that, then there are other ways to advance the frame that high relatively quickly, but if you're using pikatimer like most, then picking a different spread with a higher delay and a lower frame is ideal.
Anyways, professor Elm, Youngster Joey (Not Monday and generally suggested that he doesn't want to battle is ideal), AND the radio are ways to advance your frame. Joey is still pretty slow so you'll have to use the radio. The top right channel advances the frame a good 14-18 times per click, so it's a good way to go for really high frames. You call Elm to verify what frame you're actually on. So imo you'll do the radio advancements about 25times. That puts you at MAX frame 450 I believe (it's probably lower). From there, just use elm and the main window of RNG reporter to find out what frame you're on and go from there.
Good luck :)
I've also read diffrent radio stations advance your frame with other numbers so between which radio stations should I keep switching?