lucy24 - 7:26 pm on Apr 28, 2012 (gmt 0)
Yes, I tried That Other Search Engine's wmt last night and got the infinite-script error-- though it seems to have displayed everything I wanted to see, even after I gave the script permission to stop trying.
Some experimenting on the google site reveals that the "With Change" option is only available up to 30 days. (Today in this time zone, that's March 29.) Otherwise it's grayed-out with a laconic "error" popup. Can't be because they don't have the data-- at least for the last 45 days + 45 days = 90 days. Can't be not enough room, since Clicks and Impressions could both go into the billions (US at least) before they get tight on space. And it isn't exactly a complicated calculation. Shrug.