Cost basis proration

[RWG1950]

My customer has a lake house and has purchased the two parcels next to his for $ 135,000 - from one seller, at arm's length.
Parcel #1 is between the two houses and is land only. Parcel #2 has a house on it. He may eventually sell #2 and keep #1.
Property tax statements show assessed value for parcel #1 at $73,700 & #2 at $159,000 (he appears to have gotten a good price)
Without regard to any other costs or improvements, would this initial allocation to cost basis for #2 be appropriate ?
$ 159,000 / $ 232,700 = 68.33% of total purchase price allocable to parcel #2 ( $ 92,246 )
Thanks for comments.

[kathyc2]

Using property tax records, that would be the correct calculation. Since the chances of selling improved lot are higher, it would be to his tax advantage to have more allocated to it. I would explain this to client and give him the opportunity to get actual appraisals if he thinks a higher percent should be allocated to improved lot.

[Burke]

Since the properties are adjoining, you would think the assessed value of the land only would be the same. Perhaps they are not the same size lots? Or there is some other factor which would make one worth more than the other (excluding the improvements). That would make a difference and might affect your calculation. If the lots are equally valued for tax purposes, then the FMV allocated on Parcel #2 to the house would only be $85,300? What is the ratio of land to house on Parcel #2?

[RWG1950]

The lot sizes are different - with #2 the larger. The assessed values shown on the property tax statement are as follows :
Lot #1 land = $ 73,700
Lot #2 land = $ 109,500 improvements = $ 49,500 ( $ 159,000 total )
This is 1 purchase transaction involving 2 separate parcels, so I thought the ratio in my example might be reasonable & the easiest to defend.
However, if I understand what you are saying, if an appraisal shows the unimproved #1 to be a lesser FMV figure than the assessment and
#2 to be greater, he could allocate more of the total purchase price to #2 ? I hadn't thought of that & will let him know.
Thanks for your help and comments.