I see. Well probably the simplest approach would change your checkboxes so that the checked value is 0 and the unchecked value is the point value of each particular question. Then the way to calculate the number of points would be just:
G_Name + G_Clear + ...
You could use this in the default value formula of your hidden field.
To count the number of unchecked boxes, you could use:
count((G_Name + G_Clear + ...)[. != 0])
You can simplify the formulas a bit by renaming the checkbox fields so they have a consistent naming pattern, (e.g. prefix all the field names with "Check_"). Then the formulas would become:
sum(/dfs:myFields/dfs:dataFields/my:SharePointListItem_RW/*[starts-with(local-name(), "Check_")])
count(/dfs:myFields/dfs:dataFields/my:SharePointListItem_RW/*[starts-with(local-name(), "Check_")][. != 0])