421. If an amount received or receivable from a person can reasonably be regarded as being in part the consideration for the disposition of a particular property of a taxpayer, for the provision of particular services by a taxpayer or for a restrictive covenant, within the meaning assigned by section 333.4, granted by a taxpayer, the following rules apply:(a) the part of the amount that can reasonably be regarded as being the consideration for the disposition is deemed to be proceeds of disposition of the particular property, irrespective of the form or legal effect of the contract or agreement, and the person to whom the property was disposed of is deemed to have acquired it at a cost equal to that part;
(b) the part of the amount that can reasonably be regarded as being consideration for the provision of particular services is deemed to be an amount received or receivable by the taxpayer in respect of those services, irrespective of the form or legal effect of the contract or agreement, and that part is deemed to be an amount paid or payable to the taxpayer by the person to whom the services were rendered in respect of those services;
(c) the part of the amount that can reasonably be regarded as being the consideration for a restrictive covenant is deemed to be an amount received or receivable by the taxpayer in respect of the restrictive covenant, irrespective of the form or legal effect of the contract or agreement, and that part is deemed to be an amount paid or payable to the taxpayer by the person to whom the restrictive covenant was granted.