I was not expecting to be fighting such powerful Digimon this early. It took luck for us to fight back as hard as we did. GuzeinBuick - / @theguzeinbuick
Regarding the drop in levels after digivolving, I remember watching another ROM hack some years back, that included mega's, which had the same issue - the mega pokemon was not the same level as the one it mega eveolved from. The general consensus on that was, that the mega pokemon used a pokemon slot with a different XP-curve, meaning it took more XP to get to level 100 (from million to i.e. 1,5 million), resulting in a level drop. I'm thinking the same thing happened here - when Yuki evolved, it's evolution needs more XP, so the same amount of XP resulted in a lower level.
Oh, yeah this Rozanne battle was fierce on my end too at least towards the end. Her last Digimon is a problem especially at level 18. Luckily for me I had trained my party to be on the same level. Lost only one of my Mons but it was a sacrafice as it allowed my own Palmon to finish it off as I had to waste one of it's move in particular to take it out.