Summer tyres: either V or W – but not both ???

Hello municipality, I understand, honestly, the world no longer: Our 900/II 2.3 automatic is indicated with a maximum speed of 205 KM/H – so theoretically even H tires would be conceivable. Now we have registered 195/60R15 88V – or then 205/50R16 87W. I don’t understand this, am obviously too stupid for it. If the 195 V is enough, why not the 205r which has a lower degree of hardness ?!?! It greets… … an absolutely helpless Roland – who thought until today, he would be reasonably knowledgeable……….