policy record to be sent back to 'Review' state 90 days before valid to date

[BKash]

I want the policy record to be sent back to 'Review' state 90 days before the valid to date of the policy. ootb is sent to review 30 days after reaching valid to date. 
Need help as the following code is working for policies having valid to date more than or equal to 90 days from today's date. 
I just want the policy to be sent back to review 90 days before not more or less than 90.

var valid_to = new GlideDateTime(fd_data.trigger.current.valid_to);

var timer_set = gs.getProperty('sn_compliance.policy_expiry_to_review_timer');

var timer = parseInt(timer_set);

gs.info('timer set from system property' + timer);

if(typeof timer !== 'number' || timer < 0 || Math.floor(timer)!== timer){

    timer = 90;

}

gs.info('Validated timer:' + timer);

valid_to.addDaysLocalTime(-timer);

var now = new GlideDateTime();

var seconds = (GlideDateTime.subtract(valid_to, now).getNumericValue()) / 1000;

if (seconds <= 0) {

    gs.info('Policy review should start now.');

} else {

    gs.info('Policy review scheduled to start in: ' + seconds + ' seconds');

}

return seconds;