In NCERT Class XI Pg. 232 , 

it is given that continued oxidation of acetyl CoA via TCA cycle requires regeneration of NAD+ and FAD+ from NADH and FADH respectively.

My query is that ,for regenaration of NAD+ and FAD+ , which NADH and FADH are used.

If the NADH and FADH produced during krebs cycle is used then how can ATP be formed in ETS if they are used here again to form NAD+ and FAD+  ???

If they will not go in ETS then how ATP can be formed there.??