Interesting topic and one that's been discussed before though I don't think in this exact contect. There are many situations at
DVC and other timeshare where the cash situation doesn't equate to the points requirements. DVC was designed for full week stays and the points are structured accordingly. To take one component and use a microscope doens't give the entire picture. If you compare the weekend points vs weekday points to cash, the difference is magnified even further. The 1 Br is 60 points for a night during magic season.
There is no upgrade option of paying the difference nor should there be. Just like there may be units available for cash when none are available for points, it's a different pot of rooms.
To correct one incorrect point made earlier. DVC can increase or decrease the points for an unit if they chose. The only requirement is that they balance a UNIT for the year. Remember is unit is a group of rooms so they could increase the 1 BR and lower the studio or they could increase both for weekdays or for one time of the year. They could even increase all and decrease the GV. They could alter the split unit differential and increase it if they choose.
Also remember that the seasons for WDW and DVC in many cases DO NOT coincide. While it may be Value season for cash, it is magic season for points. DVC members usage habits are different than many that visit WDW.
As to whether the difference is appropriate, I think they are pretty close. It's already harder to get studios than everything else except GV. Look at the GV points for BWV if you want to see a premium. It's about 50% more than a 2 BR plus a studio.
If they change the studios, it's likely they'll increase them and decrease the 1 BR slightly. It is not appropriate for them to give the upgrade for a points reservation just for the cash difference and it's DVC policy not to do so. They method of doing this as explained to the OP was the correct one with some days points and other cash.