Why discount back 110 days not just 90 days? Please add some comments

What is the value of a 6.00% 1x4 (30 days x 120 days) forward rate agreement (FRA) with a principal amount of $2,000,000, 10 days after initiation if L_{10(110)} is 6.15% and L_{10(20)} is 6.05%?

**A)** $767.40. **B)** $745.76. **C)** $700.00.

**Your answer: A was incorrect. The correct answer was B)** $745.76.

The current 90-day forward rate at the settlement date, 20 days from now is: ([1+ (0.0615 x 110/360)]/[1+ (0.0605 x 20/360)] – 1) x 360/90 = 0.061517

The interest difference on a $2 million, 90-day loan made 20 days from now at the above rate compared to the FRA rate of 6.0% is: [(0.061517 x 90/360) – (0.060 x 90/360)] x 2,000,000 = $758.50

Discount this amount at the current 110-day rate: 758.50/[1+ (0.0615 x 110/360)] = $745.76