Four or eight ways of taking on practise?

[David2]

In MN 45 the Buddha said:

"Monks, there are these four ways of taking on practices. Which four? There is the taking on of a practice that is pleasant in the present but yields pain in the future. There is the taking on of a practice that is painful in the present and yields pain in the future. There is the taking on of a practice that is painful in the present but yields pleasure in the future. There is the taking on of a practice that is pleasant in the present and yields pleasure in the future.

http://www.accesstoinsight.org/tipitaka ... .than.html

My question is: Why did the Buddha not mention practise that is neither-pleasant-nor-painful?
I mean, most of the time the practise is neither-pleasant-nor-painful, isn't it?

[santa100]

In MN 45, by practicing the fourth way: pleasant in the present and pleasure in the future, if one practices diligently, s/he will reach the neither-pleasant-nor-painful state in the fourth jhana:

"And what is the taking on of a practice that is pleasant in the present and yields pleasure in the future? There is the case of a person who is not normally strongly passionate by nature and doesn't frequently experience pain & grief born of passion; who is not normally strongly aversive by nature and doesn't frequently experience pain & grief born of aversion; who is not normally strongly deluded by nature and doesn't frequently experience pain & grief born of delusion. Quite withdrawn from sensuality, withdrawn from unskillful (mental) qualities, he enters & remains in the first jhana: rapture & pleasure born from withdrawal, accompanied by directed thought & evaluation. With the stilling of directed thoughts & evaluations, he enters & remains in the second jhana: rapture & pleasure born of concentration, unification of awareness free from directed thought & evaluation — internal assurance. With the fading of rapture, he remains equanimous, mindful, & alert, and senses pleasure with the body. He enters & remains in the third jhana, of which the Noble Ones declare, 'Equanimous & mindful, he has a pleasant abiding.' With the abandoning of pleasure & pain — as with the earlier disappearance of elation & distress — he enters & remains in the fourth jhana: purity of equanimity & mindfulness, neither pleasure nor pain. With the break-up of the body, after death, he reappears in the good bourn, the heavenly world. This is called the taking on of a practice that is pleasant in the present and yields pleasure in the future"

[Zom]

I mean, most of the time the practise is neither-pleasant-nor-painful, isn't it?

Probably because this is not practice