Safe Harbor Stacked Match

[Gilmore]

Hi,

Was hoping someone would not mind reviewing the term "stacked match", or perhaps pointing me in the direction of where it may have been discussed earlier.

I've heard that it is possible to have a Basic Safe Harbor Match, a discretionary 4% of comp match, and an additional fixed match of no more than 6% of comp, which can be used to get an owner, or anyone else with similar comp and def to the 415 limit, all of which retains Safe Harbor status (ex. no Top Heavy concerns).

We have done some enhanced Safe Harbor Matches, but nothing to this level.

Is this possible, how does it work, and what are any possible pitfalls?

As always, thanks in advance for any assistance.