Brother, since you are asking for suggestions so, here is my detailed analysis.
1. Yes, you are right my word count is less because I miscounted total words. However, increasing word count is not an issue but decreasing is.
2. I don’t think have skipped important points. For instance, the sentence, “We became so dependent on machine that we don’t feel comfortable to do anything without them. In the course of time they may become our master and rule us.” is mentioned in
précis as “Machines are meant to serve humans. However, the opposite is becoming a reality.” Secondly, the sentence, “Science has given us powers, yet we don’t know how to use them. Machines require proper management or maintenance and to get fed up. If we don’t do they refuse to work and cause destruction.” Has been mentioned in the
précis as, “Machines need good maintenance otherwise, they do not work.”
3. Each and every point cannot be mentioned in the
précis. One has to generalize things and the write the precis because, this is the objective of writing a
précis.
4. The writer is talking about “our civilization”, and our civilization is contemporary or current civilization, it is not Mayan civilization or Roman civilization.
5. VERY IMPORTANT POINT: You have used first person (We) in the
précis which is violation of a cardinal rule of writing a
précis.
Précis should always be written in third person pronoun.
6. One might get passing marks in the
précis by compromising on word count but violation of basic rule like use of first person and other structural errors will be heavily penalized.
If anything perplexes you, please feel free to mention it. I will love to be corrected. The website you have mentioned, seems good. I will surely be using it.