Do you have another health issue going on to have someone tell you that 87 is too high? That sounds fantastic to me, assuming it's in the nmol/L unit. A reference range that says it should be 20-40 is antiquated - that's just to barely avoid ricketts. Optimal vitamin D levels should probably be above 60... and I've even seen it recommended to be above 100 by the Vitamin D Society.

I take about 5000 IU per day in winter, less in summer, and my last result was 110. I just looked up the lab's reference range and it's actually 75-250.