Can anyone tell me the difference between the following two svyset commands? I am not sure which one to use with my research using the NCES sponsored ECLS-K: 2011 dataset.

svyset_n[pweight=(W1P0)], brrweight(W1P1 - W1P80) vce(jk2) mse
-OR-
svyset_n[pweight=(W1P0)], brrweight(W1P1 - W1P80) vce(jk2) singleunit(centered)