If it shifted well after the ATF and filter change and then has started acting up, I would first, of course, check the ATF level. It is quite easy to over-tighten the trans pan bolts and especially when warm have a leak.
My second suggestion is to suspect a vacuum leak problem going to the trans, either the line, the line connector (they get hard and brittle) and/or a bad vacuum modulator itself.
Personally, I can't stand flaring. I know it is simply wearing away the trans unnecessarily. See if you can get it into a shop that knows the car and the trans. Often shops that respect a earnest DIYer and especially someone away from home, especially as far as you are, will really try and help.
Keep us posted.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)