A320/321 Operating Flaps with Speed breaks extended?

[FlywithPark]

Hi. I have a quick question about Flaps operation on A320/A321.
I've thought it was not a good idea to operate flaps with speed breaks extended.(there's no knowledge base about doing this though.)
but some people claims there's no problems about doing so.

is it really ok to operate flaps with speed breaks extended?
i've tried to find some clue from FCOM but i couldn't.:ugh:

please let me have a CLEAR ANSWER.

[TheBeak]

The use of speedbrakes increases Vls where Vls is the lowest selectable speed on the AP. It is possible that with speedbrakes extended Vls is higher than Vfe and so it would be prohibited to extend flap.

[topstar]

On the 320 you can use speed brake up to flap3, but you only get half speed brake with the auto pilot engaged. You need to disconnect the AP if you want full speed brake.
On the 321 you can get full speed brake even with the auto pilot engaged.
You quite often have to use it if you on an approach in flap two with gear up and a tail wind as the speed will increase and you don’t want to put the gear down at 4000ft.