If you have the option of extending your studies to get your M.Sc, it's sometimes going to be an extremely valuable resource on your CV, but, in some cases, particularly those wherein you want a particular position because it is of specific interest to you, you may find that some employers find it may make you too "expensive" for their particular project budget. You can always omit/truncate the extent of your education from your CV and include only what's absolutely necessary, emphasizing, instead, the extent of your practical experience.

Over the years, I've found that "keeping my cards close to the vest" and only disclosing details that give me advantage works in my favor. Some people take offense if you claim to have M.Sc when you don't, but few can complain if you don't make that claim though you have the M.Sc. The only exception might be if a security clearance of some sort that requires you to account for your time is involved. In such a case, I'd certainly put the correct and complete information on the security application, though you don't have to put the same information on your employment application. I've encountered several cases wherein an entirely competent individual was terminated for overstating his/her qualifications, but never have encountered one where that happened because one understated them.

If one says one has the required B.Sc yet he also has a doctorate yet doesn't make that assertion, there's nothing inherently wrong in that. The reverse isn't necessarily true, however.

It's good to have resources that aren't obvious to the casual onlooker.

RE