Converible loan notes

Hi Mike,
Thank you for making me understand so many topics that previously, were difficult to comprehend. One thing still baffles me. Sorry, ot may be a sstupid question but i need to ask. I sometimes mistake two convertible loan calculations. What is the difference? That is. E.g

Interest Years 2400* (0.91+0.83+0.75) 5976
Repayment years (30000*0.75) 22500

or

Pv principal 50000* 0.79 39500
Pv interest flows 1. 50000* 5000%= 250000*0.93 2325
2. 50000*5000%=25000*0.86 2150
ETC