Ok thank you, now I understand. I have always used Prefix for the wrong reason: I thought would require less overhead because would reduce the search to the Prefix category instead of searching the whole list. But that's not the case.
I will change them into Full commands.
The entire list of recognizable voice command phrases for your active profile are parsed when the profile is switched to and loaded, and again anytime we reload the profile or apply changes to a profile. This also occurs for any profiles whose commands are included in the active profile. Commands in profiles set as Global Profiles in VoiceAttack options are parsed when VoiceAttack launches.
Thankfully, even as it applies to full commands, we don't need to concern ourselves with overhead except for profile load time and the time it takes to apply a change to a profile (or reload that profile). When we have profiles with hundreds of thousands of voice commands, typically through dynamic phrase options which include many ways to say individual commands, we can start to see longer load times as it relates to profile loading described above.
As an example, my AVCS4 BMS Radios profile has about 4 million total derived command variations, and it takes upwards of 20 seconds to load. This tradeoff is acceptable given the amount of functionality it provides to that game, and to accomplish a goal of "any way you say it" levels of recognition including most ways I could imagine to say a given command as well as potential homophones which could be errantly produced by recognition to ensure commands fire the first time we say a phrase for a radio command, etc.
For these reasons, prefix/suffix composite commands are excellent for organizational purposes as well as making use of the {PREFIX} or {SUFFIX} tokens for additional evaluations within the actions of these commands.
This way, we can put all the common prefix commands into a single command, and then create suffix commands which require them, ("Engines", "Cargo Bay Doors", etc.). If we want to alter the beginning of these phrases, we can do so in the common prefix command used by all of these suffixes rather than having to edit a number of 'full' commands.
If we had two FULL commands,
"[Open;Close] [the;] Cargo Bay Doors"
and..
"[Open;Close] [the;] Options Menu"
...and we want to change them to include the word "Shut", we'd have to edit both of them to read [Open;Close;Shut]...
But, by having these in a single prefix, we can more easily make such an edit in a single command, the prefix.
Prefix command:
"[Open;Close;Shut] [the;]"
Suffix commands:
"Cargo Bay Doors"
"Options Menu"
...this makes more sense for a larger profile with many, many commands, but you get the idea.
Hope that helps!