might be a bit low doesed that mate.....i think the 400 iu is the recomended dose thats been around for years....but whats been shown is even on the right dose not everybody assimilates it properly ....so they could get a test done and still be found vitd deficient....and because there is little risk in overdose its suggested folk use more...
if i remember right its the vit k2 that helps the vitd3 ..not to overdose...if that makes sense.... watch that docs vids hes got some good info ...theres a few other docs on youtube as well with good info about it