Thanks for the query Hemant, The issue is regarding Challan Amount composition, since KKC is different from Service tax it should have been paid under its own head only, however once we also had such issue it was the time of Cess charge, at that time I did tried to solve the issue with dept. they told me to let it be that way, the system will bifurcate according to the return and the corresponding challan by itself and make the mistake good.
But, now since there it is KKC it may be a different story, hence I would have paid the Short Paid KKC and claimed the excess of Service tax paid as advance, if the amount is big you can try to contact dept. as I did for Cess and also if in case client is cooperative or there are regular payments for tax you may do as I have suggested to, to pay KKC and claim excess S.Tax as advance.
Hope the above points make sense to you and help, please revert if any issue is there, Thanks, Abhimanyu
Thanks for reverting, You can do so, however dont forget to intimate the dept. about the advance, you will find the intimation information on the logged in website.