I had meant to add, that I had read somewhere that if heavy dose is suspected that you can do the 5-day double dose panacur then dose with the Equest. Presumably on basis that if any worms resistant either drug you get a good swipe at all of them. However I am very conscious that worming can cause colic in horses and if heavy worm burden suspected as was case with my own mare, there is an even greater chance, hence I delayed the equest dose to time in with usual worming programme.
(I also prefer not to use the all-in-one wormers for that reason and deworm for tape worms separately, its only about £1 difference anyway and I prefer to not overload system.)