Digital BW, The Print

I use Photokit Sharpener Pro for my sharpening (and highly recommend it).  But I have 
one question.  My current workflow is broadly as follows for a colour original - all 16 
bit CS:

1. Open image and do a Capture Sharpen.  (If it is B&W then it Mode needs to be 
converted to RGB before one can use Photokit Sharpener.)

2.  Tidy and crop image, levels adjustments etc 

3.  Convert to B&W using Split Channels (Gray Gamma 2.2 space).  Final levels 
adjustments, image size etc

4.  Mode to RGB.

5. Photokit output sharpen.

6.  Mode to grayscale.

7.  Print.

My question is, given all the discussion of refined methodologies for converting to 
B&W of which Split Channels is one method, whether there are any significant issues 
with respect to doing 4 to 6?  It is necessary in order to use Photokit.  

Thanks 

Steve