Tamron 17-50 'Sharper' than Zeiss???

Forgive my attention grabbing title.

I have just been looking on Photozone at the MTF resolution figures for the Tamron 17-50, Zeiss 24 f2 and zeiss 16-35 f2.8. ALL on APS-C the A700 so the figures are directly comparable for a crop body.

This question refers only to crop cameras.

The sharpness figures at 24mm (f5.6 - f8) for all lenses were so close as to be identical, if you had to split hairs the Tamron had fractionally higher values.

Have I missed something or would an investment in Zeiss glass for a crop body be pointless in terms of sharpness for typical landscape applications?

Thanking you!