Went out to spoons for lunch, and was thinking about this while waiting for the food to come, and yes, the way I did it doesn't really work.

But your figures are for 60% growth, rather than 0.6% growth, no?

I think you probably have the right way of doing it, but neglected to factor in that it's a percentage.

Maths huh? Where is Albert Bartlett when you need him?