Hmmm! I have heard Keith Smith on the Front Office Show podcast repeat three times that a team needs to sign a 15th player to a standard contract to get the third two way deal, but I can’t find anything corroborating that. One time, he went into great detail explaining that the rule was in place so that adding a third two way didn’t start costing 15th men standard salaries, and simply let teams now stick with 14 regular season contracts.
Now, Smitty is very rarely wrong on CBA stuff, but in twenty minutes of google searching, I couldn’t find anything that mentioned needing to sign a 15th guy before you sign a third two-way. Because my faith in Smitty is so strong, I didn’t take what you posted as gospel about
signing. For example, a team with 15 players could sign their third two way at the beginning of the season, make a 2-for-1 trade and become an Under-fifteen team, and not replace him. The restrictions you listed “start the clock” on counting the number of games for two way players, instead of paying for a 15th man. This is better imho than simply forcing the team to waive their third two way player if they drop down to 14 players - it gives them time to find a 15th man.
However, CBS Spots even talked directly about the issue Smith raised:
The new CBA outlines one significant change that will affect all 30 teams. The 2017 CBA introduced the concept of two-way players, who split time between the NBA and G-League. Thus far, teams have been allowed to have two of them at a time. Now, that figure is increasing to three. Something to keep an eye on here is how it affects the final roster spot on certain teams. Owners looking to save a buck have frequently carried only 14 players with standard, NBA contracts on their roster for parts of the season knowing that cheaper two-way players can fill in when necessary. With three slots, that temptation is only going to get stronger. NBA rules still forbid teams from having two-way players active for more than 90 combined games in a season, but with three slots, teams will be able to cycle through two-way players and experiment more with ones that they like, which could steer them away from signing pricier veterans.
It's an interesting tradeoff from the union's perspective. They are undoubtedly losing full-salary jobs in this arrangement, and veterans tend to hold more sway than youngsters within the player's association. However, 30 new two-way slots will give so many more young players opportunities to prove they belong in the league that the union likely viewed the tradeoff as worthwhile.
Smitty also mentioned once that by the end of the season, the 30 NBA teams needed to average some number (like 14.3?) regular salaried players, or there was some sort of punishment. This was supposed to be some added insurance that the extra two way player simply took a paying job from some 15th man.
EDIT: One last thought. Maybe Smitty is wrong about a specific rule preventing a team from signing a third two way only if they have 15. However, the rule youngguns posted would mean that teams that had 14+3 would start the season with the clock running. Three two way deals, all active, would only last you 30 games total in an 82 game season.