The phosphatidylcholine biosynthetic process that begins with two N-methylations with phospho-base phosphoethanolamine and phospho-N-methylethanolamine, followed by a downstream N-methylation on phosphatidyl-base phosphatidyl-N-dimethylethanolamine; the process ends with the conversion of a phosphatidyl-N-dimethylethanolamine to a phosphatidylcholine.