This would stop Japan rushing the DEI which they could not do until Singapore fell in the real war.
Where do you get this idea?
Japan attacked Singapore and one week later the Borneo. They only waited to attack the Netherland East Indie, not because they couldn't, but because they hoped to keep Netherlands neutral until they were finished with Singapore and Borneo.
From here. Starting on page 28
To secure the resources of South East Asia and to quickly destroy the military opposition of the United States and Great Britain, Japan developed four strategic options:1o (see oil map, page 10)
1. Seize the Netherlands Indies, then the Philippines and Malaya.
2. Advance methodically from the Philippines to Borneo, then Java, Sumatra. and finally Malaya.
3. Reverse the above course by starting with Malaya and ending with the Philippines, thus delaying an attack on American
territory until last.
4. Simultaneously attack the Philippines and Malaya, followed by converging attacks on the Indies.
The first plan was deemed unacceptable because it would expose Japanese forces and their lines of communication to attack from both the Philippines and Malaya. The Navy advocated the second plan. It would allow early seizure of US bases in the Philippines which sat astride lines of communication, and it would allow a cautious advance south, securing air and naval
bases from which to operate in each phase. The Army, however, said that Plan Two would allow the Allies to strengthen their
defenses in the Netherlands Indies and Malaya while Japan was fighting In the Philippines. The Army favored Plan Three. It
allowed the early seizure of critical resources and delayed attacks on American bases as much as possible. But, the Navy was
opposed to Plan Three, arguing that the risk of exposing their lines of communication to American naval and air forces was too great.
This left Plan Four, which called for simultaneous attacks against the Philippines and Malaya, followed by sweeps into the Indies from opposite directions. Although this plan would eliminate the US threat in the Philippines while placing Japanese forces in Sumatra. Java, and Borneo more quickly than Plan Two, it required a dispersion of forces, advance along two axes, and posed difficult coordination problems. But, it compromised the positions of the Army and Navy and was therefore adopted.