it will pick up the tariff

[meliss]

"In our absence downvalley, Alexander has discharged with honor three cavalry squadrons of Thessaly, 660 men. ...Their mounts go up for sale. We’re all too broke to buy one, of course. The army steps in; it will pick up the tariff. The price is one bump: eighteen months’ extension of enlistment."
(The Afghan Campaign by Steven Pressfield)

Hi.
I've understood it like instead of money one should extend his enlistment over 18 months more to get a horse. Am I right?

 

[Tarheel]

I understand it as ....

Am I right?

I think so.

 

[probus]

I think your understanding of the passage is correct, but you should have written "right" rather than "wright".