The templates are spun at the paragraph, sentence and synonym level. Usually there are upwards of 1 million possible variations in the paragraph-sentence area only. That is before the synonyms are added. After 500 to 1000 uses the templates are retired, new ones are written for replacements. So you won't find much duplication in the templates area.
Spinning your text to avoid "duplicates" is a bit like wearing a bullet-proof vest to avoid being shot. For body armor, the question is, bullet-proof against what? A 9mm pistol? Or a 50 caliber machine gun or sniper rifle? The heavier the round you want to stop, the heavier, thicker and bulky-er your armor has to be. There comes a point where it weighs so much you can hardly move around.
There is a necessary trade-off between protection and mobility.
The same with spinning. If you want to get credit for backlinks on articles posted, you need about 30% difference between copies. Some say 50%, to be sure. That's good enough for backlinks, but it won't pass Copyscape. That's O.K. for backlinks because Google doesn't use Copyscape.
If you want to pass the filters at ezinearticles.com, you will need over 95-98% uniqueness.
[EZA has rejected 3-4 articles of mine that I sat down, dreamed up and typed onto a blank page, with no other text involved
Nothing being copied, original creation. Turned out that I used a particular unique, personal turn of phrase that I had used before, in another article, a year or so earlier. So I had to resort to Copyscape to find the problem and fix it. Once fixed, the articles all passed and were published.]
And no, articles coming out of IAF will probably
not pass Copyscape, not be accepted by EZA, because they were never intended to. They were intended to pass Google et. al.'s 30% rule, which includes the other text on the same page where published.
With article writing the "spin to uniqueness" trade-off is between percentage uniqueness and speed of production. IAF is intended/was designed to give the user speed in production and "good enough" uniqueness to get users the primary benefits of article writing, which are getting backlinks and direct traffic from readers' click-throughs.

Of course, spinning your own text, or taking your finished article from IAF to TBS and spinning it further before releasing could help. Also, EZA is arguably the most picky Article Directory out there. There are 1000's of others that will happily accept IAF articles for publication.
Also, if you ever do have a problem with an article being rejected for duplicate content, do what I do, check it with copyscape or
http://www.dustball.com/cs/plagiarism (free), then change whatever part of your text comes up as too similar to something else, and re-submit...
"It's better to light one small candle than to curse the darkness..."
