Don't you realize the % of "gifted" kids increased a lot in the recent years? Perhaps, since so many parents want their kids to be "gifted", the testing institutes lower the standard / increase the points, so that more kids become gifted.
I think in this cruel reality, luck is more important. Like a friend of mine has a gifted son that he was even interviewed by one of the largest public media. However, he failed all DSS admission interview. Finally, when luck came, he got a place at the best school in net 41 during the lucky draw.
IQ test is far outdated to test the gifted child and was used to make money by private clinincal psychologist.
The test was evaluated the kid amongst his age group and the normal standard in his peers.
Let say an age 3 kid suppose not knowing "+ - X /". However, some parent nowadays do their private tutoring and few kid already knew this. Then thier kid "IQ" will be over 160-170.
This is just an example how the IQ test come out.
If all the kids know "+ - X /" at aged 3, then your kid is just normal child to know this "+ - X /".
If your child only knew "+ and -" at aged 3, then your kid will be slightly RETARDED and low intelligence.