When to start taking cerazette/feanolla/mini-pill?

[fuckweasel]

I have been prescribed Feanolla (same as Cerazette) and the doctor advised me to start taking it on day four or five of my period as this would help prevent irregular bleeding. All the advice I've seen elsewhere (including leaflet with pill) advises taking on day one, though can be taken at any time in cycle.

Has anyone else been told this about reducing irregular bleeding? Obviously it's something I'd like to avoid if possible! Thanks