Robert,
Actually 5* flowers even after loosing all leaves. This winter we had only two nights of minus 9 but with violent winds up to 80 km/hour, also periods with snow and abrupt changes of temperature. No damage on Ichangquat, but 5* lost leaves on North Eastern side of a tree.
Fruits of Ichangquat are rather special, but I like them, they are not particularly soar, grapefruit like bitterness and if eaten fully ripe with a skin, the taste resembles fejoa with some pine note.
Alexander (Samodelkin), leaves on your PTxSunki look exactly like on my plant