Retail used-car prices, at $19,400 a pop, have never been higher than they were in the second quarter, according to Edmunds.com.

But here’s the thing.

Average monthly payments on used vehicles are staying relatively low.

In the second quarter, the average monthly payment on a used car was $382, according to Edmunds’ latest Used Vehicle Market Report. That’s up just $2 from Q2 of last year.

Meanwhile, new-car payments were at $505 last quarter. That’s up $14 year-over-year.

To put that in perspective, monthly payments on used cars have climbed just $13 in the past four years and $18 in the past five, according to Edmunds.

New-car payments have jumped $44 since Q2 of 2011.

So, what’s keeping monthly payments on used cars so low, amid record high prices?

Math, really.

But, more specifically: Term lengths are climbing while average APRs, for the most part, are on the decline.

In Q2, the average term length was 67.0 months. It has been a steady upward march the past five years for average APR, which was around 62 months in Q2 of 2011.

The average APR, meanwhile, was 7.4 percent in the most recent quarter. Five years ago, it was around 8.3 percent.

“Average term lengths have surpassed the five and a half year mark, all in the effort to keep monthly payments for pricier used vehicles at more affordable levels,” Edmunds said in the report.