An order of magnitude refers to the difference in exponent (or that's what I learned). To take an extreme case, 10 and 99 (1E1 and 9.9E1) are the same order of magnitude, but 99 and 100 (9.9E1 and 1E2) are different orders of magnitude.
And sure, a 10x difference is big, but all of these things are relative. Unless you're working at FAANG scale, this may not add up to much. So your job runs for 10 seconds instead of a second? Meh. OK. Ten minutes instead of a minute? OK. Ten hours instead of one hour? Hmm .. that does take a while. Maybe don't run it every hour.
Alex / talexb / Toronto
Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.