@didic thank you once again for the great review.
I'm trying to improve my style and grammar following your remarks. Also I'm using the Hemingway app as you recommend it.

About the issue with I'm using and I've been using, the interesting thing is that I first wrote I've been using, but then changed it. Now I'm clear with this, and will write it properly in the future.

About the issues like Couple of word instead of A couple of words I did the proof reading, but obviously I missed this. My untrained eye didn't spot it :). I will try to check this things with greater attention.