Firstly, I think decimal values are not used by the /wait command. And my searching reveals that the number provided is rounded up to the next whole number. So the /wait 2.5 are waiting 3 seconds and the /wait 1.5 is waiting 2 seconds. And since the GCD is 2.5 seconds, waiting less than 3 seconds means you miss the spell after the wait due to the GCD being still in effect.
Secondly, don't if you fire off this macro don't you have to dance in a circle for 8 seconds while it fires off? That's why I'm not a fan of long macros like this where everything is supposed to fire off (as opposed to the kind where you list 3 abilities in a priority order, and you spam the macro to fire off the highest priority item.
Even so... I have a macro that's similar to this (but I hate it!), but it only has 3 abilities in it. What I've noticed is that often the 2nd or 3rd item won't fire off, so I'll have to spam the macro again. With the macro above, if some of the abilities don't fire off, you're gimping your use of Fester.
The reason I use my macro is because it only fires off self-buffs, so if I have to spam it, I can.