X100 means times 100. Is the white dot set at 2 or 20? If it is set at two you system will egenerate every 200 gallons, or approximately every other day. If it is set at 20, that would be 20x100=2000 gallons.
The picture in the service manual is a generic 3200 meter photo even though it is in the 2510 manual, it is not specific to the 2510. the picture you posted would indicate a standard turbine/meter combo, not an extended range. If you had the extended range, it has a 5:1 reduction, thereby slowing it down and causing the opposite problem, not using enough salt/regenerating too late and infrequently by a factor of 5. That is why I asked specifically for a picture of the meter dial and the actual meter. It is easy to tell by the picture if the meter sticker and dome match with the pictures.
Once it regenerates tonight, watch the meter for a couple days and track how many gallons it says it uses per day. If it is excessive, you may have a leaky toilet or some other problem. Please post the picture of the meter dome.
Below are the 2 most common meter combinations used on the electromechanical 2510.
A. 3/4" Std Range (125 - 2,100 gallon setting)
B. 3/4" Ext Range (625 - 10,625 gallon setting)
Other settings for the electromechanical meter are as follows.
A. 3/4" Std Range (125 - 2,100 gallon setting)
B. 3/4" Ext Range (625 - 10,625 gallon setting)
C. 1" Std Range (310 - 5,270 gallon setting)
D. 1" Ext Range (1,150 - 26,350 gallon setting)
E. 1-1/2" Std Range (625 - 10,625 gallon setting)
F. 1-1/2" Ext Range (3,125 - 53,125 gallon setting)
G. 2" Std Range (1,250 - 21,250 gallon setting)
H. 2" Ext Range (6,250 - 106,250 gallon setting)
I. 3" Std Range (3,750 - 63,750 gallon setting)
J. 3" Ext Range (18,750 - 318,750 gallon setting)
The closest thing I could match that picture up to is the 2" standard range meter, obviously the 2510 does not come with that.
The old mechanical Fleck meter is amazingly accurate and registers very slow flow rates. A slow leak in a toilet could easily be 100+ gallons per day.