Does type of seat configuration in first class and business class affects load factor?
It doesn't affect in seats sold (usually), but of course load factor rises, because the amount of seats is lower...
To my experience, the effect happens when you rise prices. At standard price, there is no difference.
...or when there is a lot of competition. I find it better to have, say 6 premium seats and I might fill 4 or 5 of them, compared to 10 standard seats and only fill maybe 3. As started, you can then also raise the prices a little at a time to judge the effect. But generally I make more profit carrying fewer people in premium seats when there is competition.