If a person feels spaced out after chanting 16 rounds daily and more focused after chanting less rounds, what should be done?

From Ram Charan das

A devotee whom I know said to me that when he chants 16 rounds a day he finds himself out of focus

and spaced out.  So he cannot concentrate on anything throughout the day and his mind is always wandering

from one thing to another and he seems to have no control over it.  When he does not chant his 16 rounds but

as many as is possible i.e. 4 or 5 or 9 or 13  then his focus is better and his work is better.

Please advise how he can chant 16 rounds a day and still maintain focus on the work that he is doing?

Please see this answer too:

My obsessive thoughts dont allow me to chant and if I force myself to chant i feel haterful towards the Lord. Please advice.