Can a defective waiver be valid?

Does your company have an on-going tax assessment covering tax year 2012? If yes, then it is likely that you have already been asked to execute a waiver on the statute of limitations.
Following the general three-year period to assess, Final Assessment Notice for taxable year 2012 must be made not later than April 15, 2016. Thus, since this is merely three months away, the Bureau of Internal Revenue (BIR) will normally ask the taxpayer to execute a waiver.