20 odd years ago when I was learning to fly there was never a suggestion of there being a problem selecting flap during turns. It was a quite normal thing to do. The only difference to extending them in a turn compared to S&L or a Clb, or a Desc. was to ensure the 'g' limit was less than 2 (that being the C152's & C172's flapped 'g' limit'). Of course that limitation for use applies equally to all other 'g' loaded circumstances so not particularly unique to turning.
If you want them, use them. As long as any limitations are observed of course.