Apparently in iMag's playbook, a topfeed is when you have a lower NW than the country you're hitting. Even though netgaining formulas favor when a country has as close to the same NW as possible. They don't believe topfeeding is when the land difference before a hit is significantly different, such as this:

The nibbler (#146)
Nov 04/10 4:25:05 PM $14,674,254 15,921

Boobies (#127)
Nov 04/10 4:10:09 PM $16,605,948 33,670


Nov 04/10 4:29:57 PM PS The nibbler (#146) (iMagNum) Boobies (#127) (Sanct51) 5660 A (+1978 A)


Only a 211% difference. But that isn't topfeeding...