The Rs. 800 lead you are ignoring is the booking you did not make.
On creative fatigue and the CPL that climbs while nobody is watching.
Here is a pattern we have observed repeatedly: a campaign launches in October. By November it performs well. By January, CPL has risen 38%. The account manager recommends increasing budget. By March, CPL has risen another 20% and someone says 'the market is competitive.'
The market was not getting more competitive. The creatives were fatiguing. The same three variants ran to the same audience for 14 weeks. By week 6, the engaged audience had already converted or decided not to. By week 14, the budget was being spent on the least interested people in the original pool.
The signal that appeared in week 6: CTR dropped 12% week-over-week for two consecutive weeks. If someone had been watching for this specific decay pattern, not just overall CPL, they would have briefed new creative in week 7. We built a weekly creative signal audit specifically because of this pattern.