Real property depreciation question

[Steve Young]

Hello, I purchased a house as residential rental and started depreciating the property over 27.5 years with cost basis of $100,000. According to the depreciation rate table in the IRS form 4562 instructions, the depreciation rate for year 1 (1994) is 0.758%, which i calculated to $758 (100,000 x 0.758%). From year 2 to 27 (1995-2020) the rate is either 3.636% or 3.367%, which totaled to $94,545. The depreciation rate for year 28 (year 2021, the last of the 27.5 year period) is 3.636%, which is $3,636. So the total depreciation over 27.5 year according to the depreciation rate table is $98,939. There is a remaining cost basis amount of $1,061 (100,000 minus 99,939) left at the end of the 27.5 depreciation period. Why would there a remaining balance and what should I do with it for claiming deprecation expense for rental income tax purposes? Is the full cost basis amount supposed to be fully depreciated at the end? I have another property that was put in service in March of a year, and the cost basis is fully depreciated after 27.5 years with just a few dollars due to rounding calculation. Thank you for your help in advance.