they can, but i'm not too sure if it's worth it and i don't intend to do the calculations to make sure it's 100% carry forward
edit: nvm, you're right, I just checked their tips section.
edit2: so i found this:
rough translation of the 1st part basically equates to throwing a 'big' exp ticket into the dojo and general A into the dojo.
after 2.5h, exp ticket at lvl 14, general A at lvl 9.
combine exp ticket with general B gives lvl 11 general B.
combine exp ticket (lv 1) with general A gives lvl 12 general A.
therefore by conclusion, placing general A is more efficient. however, taking into consideration needing to take general out of formation, leveling exp tickets is a viable strategy.
合成時の獲得経験値=基本経験値+ 得経験値の63.9%
Combined exp = base exp + 63.9% of obtained exp