I have been using iBrewmaster recently and I really like it, and find rather handy.
However, I am really struggling with the mash temperature calculations. I use their infusion auto calculators to estimate my strike water temperature and I always come out ~4F high. I have since downloaded the (free) SpargePal app and it is almost perfect. It tends to calculate my strike temp roughly 4F less than iBrewmaster and hits my mash temp very closely.
I email their support and they were not at all helpful, they said adjust my defaults but gave me no guidance as to what, why or how.