Does fluency on a psychomotor task result from practice and a focus on accuracy?
I have never heard of this formula, but from a cognitive psychology point of view you might look the theory of expert performance (Ericsson et al., 1993). In this theory it is argued that an important factor in the aquisition of expert performance is what the authors call deliberate practice. What is meant by this is an activity, wherein someone actively tries to improve his skills in some domain. Deliberate practice is not neccessarily an enjoyable activity, as it requires effort, concentration and persistence. It is definitely conscious. 

There is quite a bit of evidence from different domains. Ericcson and Charness (1994) report findings from chess, mental multiplicaiton and music. There even is a handbook of expertise and expert performance that sums up the field, if you are interested to go deeper (Ericcson et al., 2006).

The formula that you mentioned very much reminds me of the concept of deliberate practice. I would argue that the two things basically refer to the same processes.

References:

Ericsson, K. A., Krampe, R. T., &amp; Tesch-Römer, C. (1993). The role of deliberate practice in the acquisition of expert performance. Psychological Review, 100(3), 363–406. doi:10.1037/0033-295X.100.3.363 PDF
Ericsson, K. A., &amp; Charness, N. (1994). Expert performance: Its structure and acquisition. American psychologist, 49(8), 725. PDF
Ericsson, K. A., Charness, N., Hoffman, R. R., &amp; Feltovich, P. J. (Eds.).(2006). The Cambridge handbook of expertise and expert performance. New York: Cambridge University Press.