Hatsune Miku Project DIVA Dreamy Theater Extend [NPJB00201]

Actually, both games PD 2nd and Extend can be considered as playable. Although rpcs may consider saves as broken, in fact it saves the progress. Tried to check it several times with 2nd and Extend and all completed songs by single session did not disappeared.
The other question is there only PSP saves working with these games? I mean, I've completed on perfect a lot songs within PPSSPP and saves from it didn't worked. Or I'm just played obsolete versions of these games on PPSSPP?