I know why he recommended them. Because most carbon arrow tend to shoot better if spined a little on the stiff side. In your case the 5575 may have worked OK but the 7595 will be more tolerant of any quirks in your shooting form.
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Martin Silver Star Shooter
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I'm right on the bubble between the 5575's and the 7595's as well. I went with the 5575'sfiguring I'd switch to the stiffer shaft if needed. It's been a month now and I've not even thought of switching. The 5575's are working out just fine for me.
If you're at 70 pounds you always always go for the 7595's. The stiffer spine handles the bow better. You'll also notice a little more kinetic energy due to the fact that the spine is heavier.