Using Count If But Skip Columns

I use the formula below to sum hours in a spreadsheet:

=((((SUM(B6:AP6)+(COUNTIF(B6:AP6,"x")*12.5))+(COUNTIF(B6:AP6,"d")*12.5))+(COUNTIF(B6:AP6,"m")*12.5)) +(COUNTIF(B6:AP6,"e")*6))

I would like to be able to change the range from "B6:AP6" to something which will start with B6 but only count every 6th cell up to AP 6. I could probably place a symbol at the top of each column I wish to count if needed. If I try to simply choose every sixth cell I get an error about too many arguments for the countif function The above formula is used to add hours for various shifts (symbolized by letters). For my current need I do not need the multiplier i just need to count how many of each letter appear in every sixth cell of a row.

This may be too fancy but if one formula would work to count every 6th cell starting with B6 and give me a sum , then automatically do the same starting with B7 and count every 6th cell etc...that would be great. I am trying to sum the number of each occurrences of each shift at each of 6 locations.