Regardless of the context, such limits are likely to be merely arbitrary. Another method is to set a series of factors, and leave the result to the discretion of the procuring agencies. This puts small businesses at the mercy of the buying agencies that could justify bundled contracts on flimsy grounds. The route is open to abuse without an adequate oversight and review mechanism. One could ask why this is a procurement issue at all.
Some contracts are clearly too large for any small business.
In those cases, the government can impose subcontracting requirements to channel procurement dollars to small businesses. More vigorous application and enforcement of these rules can make the bundling issue less significant. In other cases, decisions to include or exclude requirements in a single contract should be made on their merits as business propositions. Taxpayers reasonably expect their government to administer its contracts efficiently and effectively. The numbers of buildings and elevators serviced stayed the same.