Just to add in the hope it makes it clearer what I think is happening:

I don't how you metered the first of those two images you posted but taking the first one of them, the washing machine, I'll assume you metered the darkest shadow area and then pressed the shadow button on your minolta.

The darkest part is the skirting board on the bottom left of the image. Now if you had wanted to just retain full textural detail in that area, then using zone system placement, you should have placed it on zone 3. That would mean metering it and then closing down 2 stops from the metered value. Your minolta shadow function automatically gives the metered value minus 2.7 stops. Almost a whole stop less than it should have been for a zone 3 placement. If you wanted it on zone 2 (faint detail), then it would have been almost correct.
However, because you are using standard dev times I beleive you are working on a 7 stop range which means each zone is only .7 of a stop and not 1 stop. Therefore you should only have closed down 1.4 stops (2 zones lower than metered) and because your meter shadow function has automatically given 2.7 stops less exposure, you have given 4 zones less than metered (4 x .7 = 2.8 stops). The result is that the skirting board is placed on zone 1 and not zone 3. Thats 2 stops too little exposure which is why it has turned out black and the rest of the shadow values are very dark with little separation.

I hope that illustrates why you have to be careful of how you use your spot meter functions and that what you pick to meter is very important. But again, the only way to calibrate accurately is to do an actual print test to prove a zone 1 and zone 9 negative print as they should.

On the other hand, if you always intend to scan, then you have so much Dmax lattitude in the scanner that scanning and retaining full detail from the neg should not be a problem. Then you only have to worrying about giving enough exposure to get detail in the shadows and exposing for zone 3 will do that.

Real scan problems start with slide film which has a much higher dmax than negative film and usually hits the limits of the scanners capabilities.