Gift Tax, Form 709

Can the 529(c)(2)(B) election be made two years in a row.  For example, if someone contributes the following amounts to a beneficiary's 529 plan:

$51,000 in 2023

$36,000 in 2024

Can the 2023 contribution be treated as having been ratably over a five year period starting in 2023?  Can the 2024 contribution be treated as having been ratably over a five year period starting in 2024?  If this is allowed, the total amounts of non-taxable gifts will be: 

2023: $51,000/5  = $10,200 (Limit is $17,000)

2024:$51,000/5 + $36,000/5 = $17,400 (Limit is $18,000)

2025:$51,000/5 + $36,000/5 = $17,400 (Assume limit remains $18,000)

2026:$51,000/5 + $36,000/5 = $17,400 (Assume limit remains $18,000)

2027:$51,000/5 + $36,000/5 = $17,400 (Assume limit remains $18,000)

2028: $36,000/5 = $7,200 (Assume limit remains $18,000)