Bhante,
I do not think that this is what Ajahn Chah is suggesting in the text that you linked to. From my point of view, what he is suggesting is the same as what Ajahn Brahm suggests.
First of all Ajahn Chah says:
Ajahn Chah:
That which can possibly be harmful to the meditator is absorption samādhi (jhāna), the samādhi with deep, sustained calm.
So he is here defining jhāna as: samādhi with deep sustained calm. And note that it is only possibly harmful, not always harmful.
He then suggests the possibility that:
Ajahn Chah:
The meditator doesn’t want to contemplate anything else, he just wants to indulge in that pleasant feeling.
He further notes the possibility that:
Ajahn Chah:
… the mind enters calm, and we don’t want to come out to investigate anything. We just get stuck on that happiness.
So yes, if you do not use the calm mind that is the result of jhana, then there will be a missed an opportunity.
So instead Ajahn Chah suggests:
Ajahn Chah:
Here, we enter calm and then, when the mind is sufficiently calm, we come out and look at outer activity. Looking at the outside with a calm mind gives rise to wisdom.
So (for me) that says. Do jhāna (so that the mind is ‘sufficiently calm’), then use contemplation when you come out.
Ajahn Brahm gives similar advice in any number of his talks. I’ve just been reading this, for example…
Ajahn Brahm from In the Presence of Nibbana:
Just as one leaves these states of concentration, one can experience the beginnings of craving, the beginnings of the mind going out to seek satisfaction. As an arm reaches out for a cup of tea (or whatever it thinks to be joy), one sees how stupid that craving is. Craving has its measure of delight: the anticipation, the joy of activity, the doing, making, becoming, controlling. But this is delusive joy. One sees craving going out and also sees its results.
When one is developing insight based on these powerful states of concentration, something like craving, instead of appearing as an idea or concept, appears like an animal or creature emerging from the mind and going out. One sees this very clearly; also one can very clearly understand the dangers. The coarse mind can see only what is coarse and superficial. The subtle mind, however, can see the subtle.
…
So for me, Ajahn Brahm, like Ajahn Chah is suggesting that you contemplate when you come out of jhāna.
But I guess it all rests on how we interpret ‘sufficiently calm’ in the Ajahn Chah passage. In my interpretation, this means jhāna.
Dhp372 suggests this:
No absorption for one without wisdom,
no wisdom for one without absorption.
But one with absorption and wisdom—
they have truly drawn near to extinguishment.