I hate to say it, but I think there are times when service levels (and maintenance) on any ship can slip below par. Sometimes one just has a cruise with a series of less-then impressive events.
It tends to happen more often on small, short-cruise ships. Those are HARD cruises to work because the turnaround is so quick and the crowds tends to try to pack 7-days of cruising into three. They sleep less and do more, and want to try everything there is.
Staff longevity and moral tends to go down on such ships because there is no time to get to know the passengers (they become a blur), so the personalization aspect of cruise ship service definitely disappears, and there is less time to make a problem "right."
So, yes, expect less on a shorter cruise. They are bargains anyway starting at under $66 per day per person.