FWIW:
If you work always with the same font you could do it with a single text frame. The contents will be of three paragraphs.
You need three paragraph styles that use the next style feature. So you can wrap all the properties needed into one object style that use also Next Style enabled. Auto height is enabled as well:

Different point size below. Style-Middle is based on Style-Top. Style-Bottom is based in Style-Middle.
Style-Top and Style-Middle have 66% Auto Leading applied. Style-Bottom has 44% Auto Leading applied.
First baseline of the text frame is set to x-Height:

However, if you change the font you have to adapt the paragraph styles' auto leading values.
No need to adapt the styles if you just change the point size of the font, because I did all three paragraph styles with the same font size but with different auto leading values. With the solution that has the three text frames that is not needed. You can freely change the font or font size and the overall height will adapt.
Regards,
Uwe Laubender
( ACP )