[David L.]

In those sentences, you have not used a 'finished time expression'

since 1985 : the intervening time period between 1985 and now.

for 10 years : for the specified period of time of 10 years. 'He went to prison in 1985 for 10 years'.

for the past 10 years : for the specified period from now, to 10 years ago.

I've just met her : Yes. This is present perfect tense, and indicates a very recent past event and stresses the significance that there has therefore only been a short intervening period to time between then and now. The whole sentence might be: "I've only just met her so I can't tell whether it will develop into a relationship or not." That is, the intervening period from when we met to now is too short for two people to really get to know each other well.