I need help with the tempo buttons

[sugarplumsss]

I have owned t4 for over a decade. Sometimes I press the buttons for tempo and seem to see unexpected results.
I have seen tempo get much faster
and or do other unexpected things.
I have never asked about this, here.. I always assumed there must be short cuts to eg rapidly move from one tempo to another.

I am finally asking,  what, if any are the "shortcuts" with the two tempo buttons?
I would appreciate all of the ways to change tempo, besides the obvious way.
Some of the behaviors with my efforts to change a tempo, though I cannot describe these events ( they are not consistent enough for me to recall ) I am sure, something is happening that either points to my ignorance, or a malfunction, or a little of both.

[DerekA]

You can press + and - together to set the tempo to the current style default

But I don't know of any other ways that just using those particular buttons would cause the tempo to jump

[sugarplumsss]

You can press + and - together to set the tempo to the current style default

But I don't know of any other ways that just using those particular buttons would cause the tempo to jump

Thank you again

in a sense, this is good news. I have misunderstood the tempo buttons. I assumed that the odd jumping around of tempo ( not as a rule, but often enough to both irritate me and cause the misunderstanding )  was some cool hidden feature within the two tempo buttons.
I do not know why I never asked about it.
I think there is something defective in my particular T4. I have no idea how this could be, but I have no other option.

[Fred Smith]

I think there is something defective in my particular T4. I have no idea how this could be, but I have no other option.

You will find it a lot easier to get done what you want when you realize there is nothing wrong with your T4.

Cheers,
Fred

[Denn]

Hello, Yamaha have a habit of hiding settings in some obscure page of squares and ticks. Just make sure that the ticks that you want are set (ticked or not ticked). It is fun finding these pages. 
Regards, Den.
ps. My SX900 went out of the door fast because of this. I could not make it do what I wanted. It ALWAYS went to default. Now I have the SX700 and have learned more about hidden pages. My T4 works exactly as I want it. Persevere. it is fun trying to find these settings.