I just realized s.th. unexpected.
I have an Demo-Account with XY-Borker and created for back-testing the fxt-files and the hst files by the EA (b628) /portable loged in at XY-Broker and Birt's script!!
I do have an account with Metaquotes but the EA wasn't logged in with Metaquotes as they don't have all the Symbols.
Now I find all the hst-files not only in ...\history\XY-Broker but as well in
3) ...\AppData\Roaming\MetaQuotes\Terminal\1512972745DC2E3F4E6178F64AF2F622\history\MetaQuotes-New MT4 Test
All the files do have the same size and the same date built?