[Kenwood] TS590 receiver design question

[John Geiger]

>From reading the QST review of the TS590, it sounds like it has one
receiver circuit for 160, 80, 40, 20, and 15 meters, which is down
conversion and has 500hz and 2.7khz roofing filters in it, and an
upconversion circuit for the other bands, with a 15khz or so roofing
filter.

So if I am understanding this correctly there are really 2 different
receiver setups in it, is that correct?

If that is correct, why did Kenwood do this?  Wouldn't it be cheaper and
easier to just use one receiver, downconversion with roofing filters, than
it would be to add a second, upconversion receiver circuit?

Any insight on this would be welcomed.

73 John AF5CC