Bond valuation

To Get cash for pre matured Bonds, the valuation was as follows:
       $250

less than 1/2 year    $250.00
1/2 but less than 1    $255.00
1 but less than 1.5    $260.00
1.5 but less than 2    $265.00
2 but less than 2.5    $270.00
2.5 but less than 3    $275.00
3 but less than 3.5    $280.00
3.5 but less than 4    $285.00
4 but less than 4.5    $290.00
4.5 but less than 5    $295.00
5 but less than 5.5    $300.00
5.5 but less than 6    $306.25
6 but less than 6.5    $312.50
6.5 but less than 7    $318.75
7 but less than 7.5    $325.00
7.5 but less than 8    $332.50
8 but less than 8.5    $340.00
8.5 but less than 9    $347.50
9 but less than 9.5    $355.00
9.5 but less than 10    $362.50
10 but less than 10.5    $370.00
10.5 but less than11    $377.50
11 but less than 11.5    $385.00
11.5 but less than 12    $392.50
12 but less than 12.5    $400.00
12.5 but less than 13    $407.50
13 but less than 13.5    $415.00
13.5 but less than 14    $422.50
14 but less than 14.5    $431.25
14.5 but less than 15    $440.00
Maturity    $450.00