As a rule, speed isn’t good for M&A operations but, at the same time, there may be a wide variety in which high-speed operations are suitable.
For example, if the target price is negligible versus the size of the buyer (Does Google really care paying an extra 50% in a $10m deal?….).
In my opinion, as an advisor your role should be to warn your client on the risks assumed but never require the perfect timing for your analysis. The perfect is the enemy of the good!