Update (3/12/16) -- This bug has been fixed in version 1.0.2, now available on the Mac App Store.
An important bug has been detected in Balancing Act version 1.0.1 (it may exist in 1.0 also). Under certain circumstances the rebalancing calculation may fail. Calculated trades may be zero (blank) or they may result in a very large plan imbalance.
The root cause has been located and an updated version 1.0.2 will be submitted soon. Fortunately, there is a workaround. You should enter a value for either Deposit or Withdraw in the account setup dialog (reach this from the Edit menu). This value can be zero. Enter 0 (or some other value if you actually want to specify a value). Press return. The value will revert to blank if zero is entered. This step will force internal initialization to correct the problem. Be sure to repeat this procedure for each additional account, if any.
Thank you for your patience while a permanent bug fix is being implemented.