I have no idea what "desired" result you are looking for. I have watched the first 3 minutes of the video and by following the steps get the exact same answer the demonstration did.

Depending upon how you assign the resources, the 24 hours of work may be split evenly (8 hours each). In the video R1 and R2 are scheduled for 9.6 hours and R3 is scheduled for 4.8 hours.

If you want it to finish more quickly - change the work for R1 and R2 to 11 hours and change the work for R3 to 2 hours. It now finishes Friday at 3:00 pm.

The calculation by project is not incorrect - it is based upon 24 hours of work split among a total of 125% units. R1 is 40% of the total of 125% and 40% of 24 is 9,6. The same is true with R2 - hence the assignment of 9.6 hours of work. Project does not pay attention to the idea that R3 only works on Wednesday (in this scenario) - so it still assigns 20% of the 24 hours of work - or 4.8 hours.