Does this seem right RE Disability?

beacbabe

So my job says for STD the first 5 days you use vacation days. After that you are paid at the STD rate. If you have no vacation time left you will be docked 5 days but, after youre out 21 days you will be reimbursed at the STD rate...

My thing is... Why should I have to use MY vacation days and not get them back after 21 days, if the people who dont have vacation time left still get paid too??  I feel like im being penalized for having vacation time left..

Does this seem right/ fair to you? Im trying to look at it from other aspects but im having a hard time