Daniel 12:1 "And there shall be a time of trouble, such as never was since there was a nation even to that same time: and at that time thy people shall be delivered, every one that shall be found written in the book."
Is there only one time of trouble or two?
If there is one, the trouble starts before the close of probation and gets much worse.
If there is two, the one before is called the Little Time Of Trouble.
I'm not sure it matters either way.
"And at that time shall Michael stand up, the great prince which standeth for the children of thy people; and there shall be a time of trouble, such as never was since there was a nation even to that same time: and at that time thy people shall be delivered, everyone that shall be found written in the book." Daniel 12:1. When this time of trouble comes, every case is decided; there is no longer probation, no longer mercy for the impenitent. The seal of the living God is upon His people. {CET 187.4}
The time of trouble spoke of here is when Michael Stands up, so this would be after the close of probation.
I saw that the four angels would hold the four winds until Jesus' work was done in the sanctuary, and then will come the seven last plagues. These plagues enraged the wicked against the righteous; they thought that we had brought the judgments of God upon them, and that if they could rid the earth of us, the plagues would then be stayed. A decree went forth to slay the saints, which caused them to cry day and night for deliverance. This was the time of Jacob's trouble. Then all the saints cried out with anguish of spirit, and were delivered by the voice of God. The 144,000 triumphed. Their faces were lighted up with the glory of God. {EW 36.2}
When reading Ellen White (SOP), there is a time of trouble that starts before the close of probation.
On that chart above, you can think of the red line as the time of trouble which last through the different events.
Again many call it the little time of trouble that starts before the close of probation.
I saw that the holy Sabbath is, and will be, the separating wall between the true Israel of God and unbelievers; and that the Sabbath is the great question to unite the hearts of God's dear, waiting saints. I saw that God had children who do not see and keep the Sabbath. They have not rejected the light upon it. And at the commencement of the time of trouble, we were filled with the Holy Ghost as we went forth and proclaimed the Sabbath more fully. This enraged the churches and nominal Adventists, as they could not refute the Sabbath truth. And at this time God's chosen all saw clearly that we had the truth, and they came out and endured the persecution with us. I saw the sword, famine, pestilence, and great confusion in the land. The wicked thought that we had brought the judgments upon them, and they rose up and took counsel to rid the earth of us, thinking that then the evil would be stayed. {LS 101.1}
At the commencement of the time of trouble, we were filled with the Holy Ghost as we went forth and proclaimed the Sabbath more fully.28 {Mar 170.2} "The commencement of that time of trouble," here mentioned, does not refer to the time when the plagues shall begin to be poured out, but to a short period just before they are poured out, while Christ is in the sanctuary. At that time, while the work of salvation is closing, trouble will be coming on the earth, and the nations will be angry, yet held in check so as not to prevent the work of the third angel. At that time the "latter rain," or refreshing from the presence of the Lord, will come, to give power to the loud voice of the third angel, and prepare the saints to stand in the period when the seven last plagues shall be poured out.29 {Mar 170.3}
You could say trouble has been going on for some time.
"The time of trouble has commenced, it is begun. The reason why the four winds have not let go, is because the saints are not all sealed. It's on the increase, and will increase more and more; the trouble will never end until the earth is rid of the wicked." {Ms1-1848.18}