To sort out what (probably) is mentioned in the links given above. There's one simple two-line rule that comes into play here:
"Expose for the shadows..." (and I hear all of you say: "Oh no, not again..."
)
which is what you've done. As the film sensitivity changes a little bit depending on choice of developer and developing time, the ASA number isn't fixed, but it's normally somewhere at half to two-thirds of the boxspeed. 200 or 250 doesn't really matter, it's 1/3 of a stop and well within all of the other things that can vary. You're not only in the ballpark, you're in the very center of it.
Now to the second part:
"... and develop for the highlights", meaning you have to know what you want to emphasize in your pictures. If you shoot 35mm film, this usually will be a compromise, while LF shooters normally develops one or more sheets of film for any desired contrast.
Please note, this is really what will vary with different development times. It doesn't matter if you're 1/3 of a stop wrong in exposure.
If you shoot a full roll on one scene, it's simple. If you have shot it during several occations under different light you will have to compromise. But normally the time/temperature/dilution for any given combination of film and developer is given for that compromise, i.e. midday, somewhat overcast sky where the shadows are slightly fuzzy. (That is 7 stops between black and white.)
For normal shooting you can suffice with knowing about the two other types of light. I.e. full sun (9 stops difference between black and white) with sharp shadows. Then there's full overcast with almost no shadows (5 stops difference). It's quite easy to learn about how to develop the film by just looking at the shadows. A starting point would be that you develop the high contrast scene (full sun) to 80% of the recommended time, while the film from that gloomy dull gray day will look better at 125%. Now, these are starting points, but it will get you in the ballpark so to say.
Just in order to pick up and conclude what I started with: Given a 400 boxspeed film, the real speed is normally say 250. The film shoot on that sunny day will be developed less, so it will loose a little bit, to say 200. The "gloomy" film will stay longer in the soup and will gain a little bit of overall speed, so it will land on 320 or in some cases even the nominal boxspeed. As you may already have noticed, the speed of the film doesn't vary that much, even though the contrast can vary a lot.
You don't have to worry about being 1/3 stop off when setting your meter, especially as you gave it that 1/3 stop of extra exposure. All that will happen is that you may have to expose the negatives a couple of seconds longer when you print them.
//Björn
