Fertilizer top up to rescue late thin crop

What is the risk with investing more inputs in a late thin crop that already faces a high risk of yield and grade losses due to fall frost? As a rough guide, a crop needs 40 to 60 frost free days after the start of flowering to reach maturity. That takes us to late August or early September if the crop is flowering today. If a late crop is still two or three weeks from flowering, it is already at high risk of fall frost damage which could negate any economic benefit from added nutrient. Increasing the nitrogen rate will delay maturity as the plant tries to make use of this nutrient.