In Ultra Course View, the Overall Grade only offers a weighted calculation at this time. There are 2 potential workarounds that you can use so that your overall grade is calculated based on points.
Convert Points to a Weight and Use the Overall Grade Column
Set up the Overall Grade using individual item weights instead of category weights. For each assessment in your course, divide the points possible for that assessment by the total points possible for the course and multiply by 100 to convert to a percentage. Then, use that for the weight for that assessment. For example, if you have a 50 point assignment and there are 500 total points in the course, 50/500 = .05, or 5%. Repeat this step for each assessment, and make sure the total of all the weights is 100%.
Create a Calculated Total Column and Set the Overall Grade Column to Only Be Based On That Total
In the Gradebook, hover your mouse over the existing items and click the plus (+) sign. From the drop down menu, click Add Calculation. Provide a Name for this calculation (like "Total"). In the Functions and Variables area, click Total. Click Total again on the right side of the screen, and select all of the categories or individual assessments to include in the total. Click the Save button.
Then, you can set up your Overall Grade using individual item weights, but with 100% as the weight on the Total you just created. Click the Exempt symbol (circle with a slash) to remove all other items from the calculation and then click the Save button.