Multiple entries to Macau

I have a Singapore passport and am currently waiting for my husband's work visa to go through which will take a couple of months at least. He is on a British passport and once his work visa goes through, he will be able to sponsor me. In the meantime, I am on a tourist type. I was given 30 days stay, and I went to Hong Kong for the weekend when mine was up. On my second entry to Macau, I was given only about 3 weeks. I am hoping to go to Hong Kong again when mine expires, but am worried that I will be refused entry on the third time. Why have I been given less than a month on my second entry to Macau? Will it be better if I go back to Singapore then enter Macau, than from Hong Kong? Thanks!