DOS, Hopefully I understood your post correctly... If there's an official answer it is 'sometimes'. It'll depend on the top tube length, which I think of as the critical frame measurement. Using my 56 cm '89 crit Cannondale as an example the 1.25 deg. steeper HT angle required a longer TT than a same sized non crit road frame. It could have also been achieved by using the same TT, but shortening the DT, which would've kept the reach the same for the two frames. When I wanted a newer frame to build I found the 58 cm 2.8 frame had nearly the same TT length as the '89, within 1/2 cm. A difference in ST angle will have the same 'maybe' effect.
The reason I researched the 2.8 is that I read the same, or nearly the same info as you. I think the info is valid, but again it depends where the steeper HT or ST angle was accomodated.
Brad