Some organization, I don’t know which, said the maximum safe dose is 100 micrograms per day.
If you have more vitamin d than is possible for a human being to have from being in the sun, I think you have excess vitamin d. With half the dose you mention, you would have a lot more than that.
You appear to be correct:
Recommendations for how much daily vitamin D adults need through diet have changed over the years. Currently, different recommendations exist. The Institute of Medicine has placed the recommended dietary allowance, or RDA, for vitamin D at 600 international units (IU) per day for young adults and 800 IU per day for adults older than 70. Other experts suggest that adults’ vitamin D needs are much higher. For example, the Endocrine Society recommends up to 1,500 to 2,000 IU of vitamin D daily for adults.
Mayo Clinic recommends that adults get at least the RDA of 600 IU. However, 1,000 to 2,000 IU per day of vitamin D from a supplement is generally safe, should help people achieve an adequate blood level of vitamin D, and may have additional health benefits. While there are no guidelines for checking your vitamin D blood level, it may be prudent in people with osteoporosis or certain other health conditions. Discuss with your health care provider if it may be beneficial to check your vitamin D level.
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-how-much-vitamin-d-do-i-need/