It’s important to remember that MoneySMARTS calculates figures such as your expected surplus and jar values at a point in time, meaning that surprise income that is not ordinarily accounted for and not ordinarily received for such as redundancy payouts, Christmas bonuses, etc. should be treated as such, and not factored into your ongoing calculations (page 62 of the Make Money Simple Again book).
When recording your account balance in the checkup account, the additional increase in your month-on-month balance captures the additional income received as a surplus for the year.
Also, think about the ad-hoc income you may receive. When it comes to irregular, inconsistent, or unlikely income, such as the out-of-the-blue random Christmas bonus you got last year from your employer, it’s best to treat this as a surprise income and not factor it into your ongoing calculations.
With regards to lump sum expenses, there are plans to address this so it doesn’t adversely affect the reporting balances in MoneySMARTS in the near future as part of a major MoneySMARTS release, though this will be some months away.