Yes, you're right, emanuela. A basic mistake. I realized some hours later, when I was beyond the reach of the Internet, that I should have explained it along the lines of:

1 order of magnitude = x 10
2 orders of magnitude = x 100
many orders of magnitude = (say) x 10^7 (10 to power of 7)
many many orders of magnitude ~ x 10^(7x7)-ish??
etc

Makes the original exaggeration even more far-fetched.