According the solution the premium of 10-year MBS is 0,95% instead 1,95% (1% related to spread of 10-year over 1-year Treasury note and 0,95% related to spread over 10-year Treasuries).
The reason is probably the note in the table where is noted that the premium includes maturity premium, but however in the table is given info that MBS premium is 0,95 higher than 10-year Treasuries.
Is the note reason for the result? If Yes, Why the note is more relevant than information in the table?