For the millionth times- there are no such rules that your diploma has to be after bachelors! Neither it means diploma started after 10th is considered part of the bachelor degree. And also you have no choice to claim points as per your wish because system does it automatically. Your education points entirely depends on your level of education mentioned in your eca report. Even if you have done a bachelors degree only attending final year and eca says it is a Canadian equivalent bachelor degree then you will get points for a complete bachelors degree. Similarly if you have started your diploma after tenth and your eca says its a Canadian completed diploma equivalent then you will get points for diploma. Now when you will add both credential in the system, it will award you points for "two or more" degrees. Here I am posting my comments from other threads.
You will receive points for "Two or more certificates, diplomas or degrees, one must be a program of 3 or more years". Both of your credentials must be from "Recognized Institution". Please check your report.
To understand the whole "two or more degree' equivalency please refer to this post by@Maverick28
https://www.canadavisa.com/canada-immigration-discussion-board/threads/two-or-more-certificates-degrees-or-diploma-lets-get-it-sorted.560332/#post-6996995
To check your credential's Level of Education, please go to this site-
https://www.canada.ca/en/immigration-refugees-citizenship/services/immigrate-canada/express-entry/documents/education-assessed/read-report.html
Now for your specific query I am going to demonstrate how enter your credential correctly in EE profile-
For "Come to Canada Tool" please select level of education as "Two or more certificates, diplomas or degrees, one must be a program of 3 or more years"
Now, I am showing you how to enter details of your credentials in Express Entry Profile. After you enter both credentials and submit the profile, system will count your points automatically and award you points for "two or more degree'.
You will have following questions to answer in your EE profile to add your Diploma-
Name of the credential: name of the diploma
Institute name: should be awarding university name (not the college name, check ECA report)
Start Date: diploma start date
is it your current study? answer NO
End Date: diploma end date(usually last day of exam)
Completed Academic years: calculate duration.
Fulltime/part time: select one
Level of education: 2 years program//bachelors degree or three or more years program. (Which ever applicable to you)
Have you completed Canadian degree during this time? answer NO
have you got ECA? answer YES
which organization: WES
reference number: WES ref no (it ends with 'IMM')
ECA report Date: Eca completion date (check report)
Level of Education as per the ECA: 2 years program
Click Save and Add, it will show at the bottom of the page, you can add your bachelors after.
You will have following questions to answer in your EE profile to add your Bachelors-
Name of the credential: name of the bachelors
Institute name: should be awarding university name (not the college name, check ECA report)
Start Date: degree start date
is it your current study? answer NO
End Date: degree end date(usually last day of exam)
Completed Academic years: (calculate duration including exempted years)
Fulltime/part time: select one
Level of education: Bachelors OR three or more years program
Have you completed Canadian degree during this time? answer NO
have you got ECA? answer YES
which organization: WES
reference number: WES ref no (it ends with 'IMM')
ECA report Date: Eca completion date (check report)
Level of Education as per the ECA: Bachelors OR three or more years program
Hope it helps. Good Luck!