[Idiom] get it down to a science

[Eway]

Dear Teachers,

I read the following paragraph from The Repossession Mambo by Eric Garcia and I don't understand what the last sentence means. Can anybody explain to me?

The Credit Union ( a company that sells artificial human organs)has always done a good business. From the first year of their inception, even with all the built-in liquidity drops, they have never once taken a loss on quarterly earnings. People buy artiforgs (artificial human organs), plain and simple, and with today’s generous interest rates, there’s no end in sight. There was one point about eight years back when the average loans were coming in at forty, almost fifty percent, at which point a lot of people chose to take their chances with modern medicine rather than the Repo corps. End up with more than one artiforg, and the payments can stack up quick. So the Union scaled back the percentages until the applicants started flooding back in. It's a delicate balancing act, but they've got it down to a science by now.

 

[Raymott]

It's means that, in the beginning, getting the percentages right, etc. was guesswork, and trial and error. Now, it goes like clockwork - almost like a scientific law. They know the exact effect they will achieve from any act or decision.

(Of course, science is not really like that, but it works that way as a metaphor).