Don´t sweat the small thing, Marcelo. We all strive for learning (and somewhat for perfection at some degree) and sharing knowledge with others.
We can see that you did your homework and your best and is eager to help, so that is what counts.
Be aware that we appreciate your participating and your answers will welcome.
As for Thomas, he is an asset, a maestro, we learn a lot from his insightful and usually accurate, being a native (what is good to us, since he offer an American view of things) he is direct and concise, many times someone can take it for bluntness, it is not.
Having lived in Brazil (and in other countries where Spanish is spoken), Thomas knows a lot of our culture and a great deal of our language, so his answers are dependable and we only have to gain from his experience (not to mention that he has years in Brazilian English Forums, before this one).
That doesn´t mean that you shouldn´t deal with the answers of any Expert with a pinch of salt, everyone makes mistakes, and sometimes we can be slightly misled by some cultural aspect, for example. When you think something is amiss, please let us know, ask, do something about it.
As for the answer given by Thomas, I am convinced that it was an insightful and really good one. I (or others) would mention if I (someone else) found something worth noticing or polishing (Portuguese-and-translation-wise).
So, chill out buddy, don´t sweat the small stuff. And congrats on your colaborating attitude and positive inspiration towards English learning, we can see that you take the learning English seriously, that´s good (I mean, in a good sense). Count on us.