Many people find that the number won’t stay put. It merges with the out-breath so that you’re sort of exhaling the numbers. I think that’s fine.
The first stage is more connected with the out-breath anyway, and the fact that the number has a way of integrating itself into the exhalation just reinforces that association.
It’s all too easy, especially when first learning meditation, to find that we get caught up in wanting to do things “perfectly.” We look at our current experience and compare it unfavorably to some imagined state that we tell ourselves we “should” be experiencing, and of course we feel unhappy. There’s no quicker way to make ourselves miserable than to make unfavorable comparisons between how we think we are and how we think we should be.
So we need to learn to let go and to accept that sometimes things don’t happen the way we expect them to.
In fact it’s probably a good idea, when something like this happens — the numbers not going where we expect them to go — to take a sense of gentle curiosity into the experience. Perhaps the fact that the numbers are merging into the outbreath (which is all about letting go) is helping us to meet a need to let go more.
Having said that, I think it’s good to work gently at getting the number to go where it’s “supposed” to go — in the space between the out-breath and the in-breath. There are good reasons for this that we’ve gone into elsewhere. But don’t force it. Be gentle. Be patient.