First, the reason the "peak hourly retrieval rate" of "1 gigabyte per hour" is there in the article is to answer this question. At a relative allowance of 5.12 GB/day and 1 GB/hour transfer rate, that gives you a "peak hourly retrieval" of .79 GB (at 5.12/24, your first .21 is free), and so we multiply:

.79 * 720 * .01

Giving me a little less than $6.

Now, do you think Amazon is likely to think they can get away with selling a service that charges you $22k for a 3TB retrieval?

Second, you have ranged GETs and tape headers; use them to avoid transferring all of your data out of the system at once. [Edit: looks like ranged GETs are on job data, not on archival retrieval itself. My bad.]