Section 54F is not applicable in your case. It should be Section 54 as you're dealing with LTCG on sale of house property.
Section 54F would've been applicable if it was sale of any long term capital asset, other than house property!
There is no such restriction as you've mentioned in (d) in Section 54. Such restriction is only applicable to 54F and NOT 54.
Also up to 50 lakhs can be invested u/s 54EC within 6 months from the date of sale of the long term capital asset (house property, in your case) in LTCG Bonds issued by NHAI / REC, lock-in period is 3 yrs, yearly interest @ 5.25% p.a. The simple interest is taxable on accrual basis but the principal i.e., 50 lakhs becomes entirely tax free on bond redemption at the end of 3 yrs!
Say for example:
House sold on:
25/08/2017 (FY 2017-2018)
Can invest maximum of 50 lakhs in LTCG Bonds u/s 54EC within:
25/08/2017 + 6 months = 25/02/2018
Return filing due date:
31/07/2018
Have to invest the whole/remaining LTCG amount in house property before return filing due date:
31/07/2018
If can't invest in house property before return filing due date, have to put the whole/remaining LTCG amount in CGAS before return filing due date:
31/07/2018
After putting the LTCG amount in CGAS before return filing due date,
(i) OPTION A: you've to invest in a ready to move in house property within:
25/08/2017 + 2 yrs = 25/08/2019 or,
OPTION B: you've to invest in an under-construction house property or construct your own house and must obtain Occupancy/Completion Certificate within:
25/08/2017 + 3 yrs = 25/08/2020
(ii) if no such investment or only partial investment is made, then that whole or remaining amount lying in CGAS Type A and/or B account(s) becomes taxable @ 20% as LTCG in the following FY:
25/08/2017 + 3 yrs = 25/08/2020 = FY 2020-2021
So, when LTCG amount = 2.5 crore, then:
u/s 54EC = 50 lakhs
u/s 54 / 54 (CGAS) = 2 crore
OR,
LTCG = 2.5 crore
u/s 54 / 54 (CGAS) = 2.5 crore