Salams dear repected ulema,

I was praying taraweeh in regents park masjid last night.
In the last four rakah the imam prayed it as one complete unit, with one taslem, without performing jalsa in the middle. Is this permissable?

I would also like to know the differences between the shafies and the ahnaaf on the prostration marks when performing salah.

JazakAllah Khair.