That can be a factor but if you had time to make a short post, why not finish the whole thing? And according to what the Op brought up, it showed that he did this over a period of different intervals so what you're trying to say is, at the time he made those few worded posts, he was on the job?
I know you're just giving your own impressions of what might be the reason why Saint-loup did what he did but you know, if you've got a day job that may affect your forum time, you could make a plan that would suit both the job and the forum posts, so that you don't get issues like this.