I was just saying that it is considered an upconversion just because the resolution is high, not that I consider it an upconversion (which I do because it technically is in the linguo of it all).
Also, 1080i might share the same general amount of khz per 60hz as 540p, but that doesn't make it the same in any other way.
1080i consists of more pixels in a different way than 540p or 720p since it's interlaced.
Also, converting 720p to 1080i is one of the easiest conversions besides 480i to 480p. The resolutions are different, but the overall requirements for the hardware are very similar.
Progressive scan is more intensive on hardware, but 720s lower resolution makes up for it compared to a high resolution 1080.
Its like this: (to make it simple)
Seven Twenty Res. = 1
Progressive Scan = 2
1+2=3
Ten Eighty Res. = 2
Interlaced = 1
2+1=3
Now I'm not trying to make that a big deal, I admit it's nothing really. I know its nothing technical or really correct, but its just something I've been trying to say Hardware intesive wise.
And I'm not sure how hard scaling a 720 image to 1080 would be, but if you can play HD 720p stuff in 480i, then 1080i shouldn't be much of a problem.