Mistake by institute in excess leave calculation

Hi,

I had submitted for 105 completion of Industrial training 15 days back and was expecting some extention so enquired about it with articles dept. They told me the excess leave is 134 days which matched with my calculation.

As I had to fill up form 103 pending the institute's letter regarding excess leave so I added 16 days (safety margin) in my extention period (total 150 days that is 5 months). Now while submitting Form 103 i enquired about extention period again and now they are saying excess leave is 154.

Please check my calculation of excess leaves and guide me.

Total period of articleship                  1124

Total Leaves taken                              275

Total Days actually served                 849

Entitlement of leaves                          

(1/6th of Days actually served)          142

Excess Leave                                       134

I think they have calculated leave entitlement as 1/7th of actual days served.

Please guide me with the rules and whether my calculation is right.