The earlier poster's vitamin D levels sound about right. However Freddy, why don't you try take a trip down south during summer and responsibly get a healthy amount of sunshine and natural vitamin D?
I've checked the Maxalife site you mentioned. It looks like a credible company and the vitamin d product looks good, especially considering they use cholecalciferol. Maybe use the Maxalife product in winter and then during summer, soak up a healthy amount of sunshine. Don't worry, I said 'healthy amount of sunshine' so please don't banter me! ;)