Will the successful breeding pair surely succeed again?

[Tinatanos]

Until now, I have relied on my experience to succeed in breeding.
But now I can see the statistics on breeding in the "Records".
But before looking at the statistics(Records), my hypothesis so far is as follows.

-Hypothesis
-Successful breeding pairs successfully reproduce again with a high probability.
-On the contrary, it is also true that pairs that fail to reproduce are difficult to succeed in breeding.

-Method
Use statistics in the "Records".
Click the "Breed again" button by randomly selecting the pair with "Offspring".
By conducting 100 times like this, we check how successful breeding has been.
To verify the opposite hypothesis, randomly select a pair with the message "The Breeding was unsucceeded" and press the "Breed againg" button.
Similarly, 100 times are performed to see how successful they are at breeding.

-Result
-Number of breeding successes of successful breeding pairs: 45
-Number of breeding successes of failed breeding pairs: 41

-Conclusion
I thought a successful breeding pair so far would succeed in breeding with a very high probability, but so far there has been less difference than I thought.
However, it was confirmed that there was a difference of about 4 times based on 100 times.
If success in breeding is absolutely necessary (for example Quest), in my case I will use the method of reproducing a successful breeding pair again.