can you help me cat value my russian stamp please...

by christopher kenny
(bolton, lancashire .uk )

the information i have has come from loralstamps.com.....the first is a 10 kon stamp issued 1909 . loral has one for sale for £500.. what is the true value and what is its cat number as i suppose that loral has reduced from the actual cat value,...and also are my error varieties i have a pair of 10 kon stamps with a really nice shift error and dot flaw...and 2 possibly 3 more shifting errors .. i dont have any information apart from the pair error is the more scarcer one and hope that you can help me identify my stamps please...they have a place but no name and its been weeks now and they still have not got a reference number or guide price..thanks in advance. please find scans of the stamps attatched. ...