The Total Score or Maximum Possible Score for your Point Table can be calculated by adding all the point totals for each sub factor together OR by adding all the weights together and multiplying by 10 OR by creating a sample job and evaluating it at the highest level for each factor (see how do I evaluate a job).
The Maximum score for the standard HCI Point Table is 1000 points, which is generally accepted as a standard point total for Point Table based job evaluation systems. Legislation does not dictate the point total of your evaluation system, but it does need to have the ability to evaluate all the jobs in your organization and create a hierarchy of them that can be banded into similar valued roles.
Any changes to the weighting of the sub factors will change the maximum total accordingly if the Calculation type if it is not set to "Custom". You should only use custom point totals if you are sure you know what you are doing. If the point totals do not change immediately, simply refresh the page (using your browser refresh button) to see the updated totals. Note, if you have "Custom" calculation type on your total may not exceed to the maximum for the sub factor based on the weight (10 times the weight).