i have a mate who uses that or a similar programme. me and brother were interested in how it work and have worked out the math formula it uses. i don't MT SnGs anymore so i've no use for the programme. i just like to be able to work out the math if i need to
the guy i know who uses it says it's basically like printing money though. as long as you MT at a limit where the players respect the stratergy. basically anything north of $40 buy-ins.
It is irrelevant what buy ins and whether you are multitabling, as to whether an ICM calculator is of use, or value for money. I have SNGPT and i would recommend it to anyone, who is taking sng's seriously.
For higher buy ins people are generally playing closer to optimal strategy but this means you can just plug in more accurate ranges, generally the better the player they will push wider and call tighter in the end game. Vice-versa in the lower buyins. This is of course situational but you get the idea. You get to the point in the higher buyins, where everyone is playing near perfect and you get something called nash equilibrium where there is balancing point where everyone is playing perfectly hence the word equilibrium. So for lower buy ins, you simply adjust the ranges to the players and icm is still completely valid.
As for multitabling you seem to be under the impression that there is better way to play than push/fold if you had the time. There isn't really, playing less tables just means your ranges on opponents should be more accurate and therefore you can tie this back in with icm to make more correct decisions.
Simply the question is $80 worth it to vastly improve your sng game, the answer to this is mostly certainly yes, unless you are playing micro stakes.