Value in SES exceeding PO

Dear all,

I am having a service PO with one service line item and with price 50000 , and SES is created with the same value.

But in the same SES, system is allowing to enter more value as second line item, so that the value is exceeding the PO, Unlimited check is not enabled in PO as well as ESLL-UEBTK also not enabled.

Please let me know why it is so.

Regards