WILL DECLINE ITA REDUCE MY CRS SCORE FROM 981 TO 381

[Jobaira]

Currently I am OINP nominated and because of this my score has been increased from 465 to (381 + 600) = 981.
Most probability I will be getting ITA in next round. I need to decline this ITA.
1. Please advice if I decline ITA then will my score reduced to 381?
2. If not then for how much time my score will be 981. Currently OINP ask applicants to accept OINP nomination within 1 month. Does it means if i decline ITA then OINP score will be valid for only 1 month or for how much time?

Any pointers will be helpful.