There are many variables the come into play regarding the time charter amount displayed within the time charter bill.
The reason why the Time Charter Bill displays a different amount than the "expected“ Monthly rate set within the contract is due to the number of days in the previous month (February 28 days) and the start of the period (12:45).
Having less days in the previous month creates a higher generalized rate for the month of February compared to March. Therefore, the remaining 11.25 hours or .46875 days of February’s Hire will be greater than the 11.25 hours or .46875 days missing from the Monthly hire of March.
1062500/28= 37946.42857*.46875= 17787.38839
1062500/31= 34274.19355*.46875= 16066.02823