Prcing validity date

Dear all ,

When i maintain the Price at VK11 e.g for 100 Rs. , and having some validity range for e.g. valid from - 01.05.2016 and valid to 31.12.9999,

now as on date rates are changed , now the rate is 120 rs. , again i maintain this new rate at vk11 which is valid from 26.05.2016 and valid to to

31.12.9999 ,

Now , when i am going to check the report at V/LD , considering std. parameter "28" , against the same material as above , i got the report as ,

the first rate i.e 100 Rs. of material is automatically close and date range shows valid from 01.05.2016 - valid to 25.05.2016,

so , from which setting this type of automation is done in sap

Please guide me on above

Regards,

Sourabh