[kareemsabri]

It seems like a distinction without a difference. The investing outcome is identical, so why does it matter that your job pays you out over the entire year.

[mbesto]

The difference is the following:

Scenario 1 [S1]: I have $120,000 in cash.

Scenario 2 [S2]: I expect to make $120,000 in cash over 12 months, equally once a month

On Day 0...

S1 - I have two choices: put all $120k in the market ("lump sum") or DCA is over 12 months.

S2 - I have no choice but to DCA it.

If I choose to DCA in S1, then I could have made more money by lump summing (depending on market conditions). This is basic TVM.