It was the previous update that changed the affection required per girl. THIS update didn't increase the affection required per girl.
Yes, it is always 417 money per affection point. The higher rarities are a bulk item that require less clicking and can be used to supply affection faster. It also makes sense, you have to put in less work to achieve the same result with higher item tiers.
The way it currently works means that the amount of girls you have before you get a girl drop is more or less irrelevant to the time it takes you to upgrade a girl. Basically, when you have 50 girls and get the 51st, it takes around the same time to get enough money to upgrade the 51st girl as it would when you have 100 and need to get money to upgrade your 101st girl. Due to the money from the bosses changing it a bit, it's not exactly the same, but the difference isn't too big.
A simplified explanation might help. For the sake of this explanation, let's assume every girl gives exactly 1000 per hour and you don't get money from anything else and that the base upgrade cost is 100k. If you have 50 girls, you would get 50k per hour and you spend 5 million to upgrade the girl (which takes 100 hours). When you have 100 girls, you will have double the income (100k/hour). Your newest girl will also have cost double what you paid for your 50th girl (10 million). To get that 10 million, it takes you the same 100 hours.