We need to boost our T/W L.A. signal a bit (10-15db) as it's just on the verge of dropping the channels coming in on the adapter.  Add one RG6 to the splitter and signal on say ch. 606 or 444 drops.  Take that feed off and the channel comes back.

T/W says "not our problem"

We can use the Legrand VM2201-V1 RF Digital Cable Amplifier, but that only amplifies up to 1002 Mhz...  And I believe the channels we need are higher than that range....

Set up:

(1) 8-Port T/W installed splitter (6 ports used - 2/Tivo DVR, 4/Tivo Mini MOCA)
(2) Tivo Romeo (with T/W cable cards, (1) MOCA+eithernet)
(7) Tivo Minis (3 eithernet, 4 MOCA)

When I have the full system above connected I get about 16db on the DVRs. When I disconnect 3 of the RG6 MOCA connected to the switch it jumps to about 30 and all channels come in.

Sorry if that sounds confusing, but thoughts on how this can be boosted?

You should be able to get a Time Warner approved amp through Time Warner, it most definitely their problem.

Where are you getting those power readings from? 16db is more than enough signal.

I'm going to guess that you talking about the TIVO 'DVR Diagnostics' screen. And if so, that is NOT dB levels. That is just a reference scale to go by = 0 is no signal at all, 100 is max.
TIVO recommends you have between an 80-99 signal on that meter. Below 50 and things start to screw up. 15 certainly would cause problems. And even 30 should be causing some problems, maybe haven't noticed yet.
Also on that screen, that is very important, is SNR. Should be at least 23dB (yes, that is shown in dB).

Sounds like you do need an amp (although other things could still be an issue as well). How much gain you actually need on the amp, would be determined by a digital meter - to measure actual signal levels.
Or... if you could find an adjustable amp. Start at the lowest setting and turn it up, until the TIVO signal bar is at 99 (or the highest number it will go at full).

I have used a CE Labs 6001 with good results. It has 20dB of gain and is adjustable down to 0dB gain. Maybe discontinued now thou.