[Grammar] After I got this device, my reading has siginificantly increased.

[Sarah-Betty]

Are the sentences below fine?

After I got this device, my reading has siginificantly increased.

Since getting this device, my reading has siginificantly increased.

Since I got this device, my reading has siginificantly increased.

 

[emsr2d2]

Are the sentences below [STRIKE]fine[/STRIKE] OK/correct?

After I got this device, my reading [STRIKE]has[/STRIKE] significantly increased.

Since getting this device, my reading has significantly increased.

Since I got this device, my reading has significantly increased.

Note my corrections above, particularly the correct spelling of "sign​ificantly".

 

[Sarah-Betty]

Thank you teacher.

Why the first one is incorrect?

Does the second "since" mean "because" ?

 

[emsr2d2]

[STRIKE]Thank you teacher.[/STRIKE] Unnecessary. A click on the "Thank" button suffices.

Why is the first one [STRIKE]is[/STRIKE] incorrect?

Does the second "since" mean "because"?

Note my corrections above.

The first is incorrect because we don't use the present perfect after "After".
"Since" means "From the time that" in sentences 2 and 3.

 

[Roman55]

Although the word order is perfectly correct, I would tend to say increased significantly in all of those sentences.