Did you run previous accruals before 30.04.2015.
You can check it with TPM13 transaction (plese post screenshot)
If yes, next time you start accruals system doesn't show you accrual because you have run it.
About "Incl. key date" field.
If i was able to create transaction similar to yours, then you have similar screenshot of flow on 30.04.2015. Calculation period is 31.03.2015 - 29.04.2015.
If you check "incl. key date", then system consider 30.04.2015, but for you transaction this date is new period - so it shows you 1 day accrual - period from 30.04.2015 to 30.04.2015.
