they were equally available to the IRS at the time it took its position based on Baker’s report. (3) Based on the foregoing, it is clear that, before the IRS issued the notices of deficiency, the estates had provided enough information to the IRS to alert it to the fact that the in-kind partition described in the Baker report was not viable, and that his estimate of the costs of a hypothetical partition in kind was speculative and unsupported. The IRS has a duty to examine the information provided by taxpayers and to make some effort to substantiate a demand for payment of additional taxes in a notice of deficiency. See Estate of Johnson v. Commissioner of Internal Revenue, 985 F.2d 1315, 1319 (5th Cir.1993); Portillo v. Commissioner of Internal Revenue, 988 F.2d 27, 29 (5th Cir.1993) (<HOLDING>); Lennox, 998 F.2d at 248 (IRS’s suspicion
holding that district court had not abused its discretion in denying plaintiffs motion to amend complaint holding that tax court abused its discretion in denying costs where notice of deficiency lacked any ligaments of fact and was issued on the basis of an unsubstantiated and unreliable 1099 form holding that bia abused its discretion in denying motion to reopen holding district court abused its discretion in admitting state court findings of fact holding that a second deficiency notice issued for a taxable year was valid where it determined a deficiency in a different type of tax than did the earlier deficiency notice