HEY! I was checking my car loan payments and I'm very confused because in some payments the interest goes higher than in other months but the principal balance is lower, that does not make sense for me because is less money that I owe. I don't know if I'm not understanding something or this is an error in the bank. I made an excel to make it more clear.

For example: in payment 3 the total payment was $365.10 and 307.80 goes to the principal amount and 57.30 to interest amount. then I made to extra payments with no interest and then payment 6 again $365.10 but now $269.73 to principal amount and $95.37 to interest amount?? I don't get it.

Also forgot to mention, the credit is for 48 months (If I divide the finance charge between the 4 years it should be $657 per year of interest and I still having 5 months to complete a year and already pay $601 in interest)

Please help me :( If I can explain it better please let me know! thank you so much