I found the chapter you were referred to and it is has clarified how is the Morsi and Alexander drag law formulated in Fluent. 

For people who might have the same question in the future : Fluent uses the coefficients from the above image with only difference found in the regions defined. Moreover, the last particle Reynolds number is defined as Re_p>= 10000 which is a valid assumption up to Re_p <= 2*10^5