Small nit: Wait(50+rand(10)) is probably closer to what you want to get about a minute between executions. As stated your proposed execution has an average about 30s execution interval with a variance of about 17s. If you’re talking about a random sleep on a 1 minute interval, this actually results in a possibility of 120s between tasks, also not what you want.

But yeah, as soon as you start using Rand most people make all sorts of mistakes. And if you’re using C Rand, don’t. It has other statistical problems.