The extra space after the c has always been a problem on FamilySearch as well as on the LDS 1881 census CD-ROM version, and it doesn't appear that you can get round it with wildcards.
If I search for M*c*pherson in the SP index to the 1881 census I get 10,913 results, but I only get 1,654 in the LDS version.
If I replace M*c*pherson in the LDS search with M*c pherson (i.e. replacing the second wildcard with a space) I get 9176 results.