计算结果有误差 我该如何调整

[Huxiaoyou97]

我的代码如下

package main

import (
	"fmt"
	"log"
	"strings"

	"github.com/pkoukk/tiktoken-go"
	"github.com/sashabaranov/go-openai"
)

func main() {
	ins := []openai.ChatCompletionMessage{
		{
			Role:    "user",
			Content: "Hello!",
		},
		{
			Role:    "assistant",
			Content: "Hello! How can I assist you today?",
		},
	}

	fmt.Println(NumTokensFromMessages(ins, "gpt-3.5-turbo-0613"))
}

func NumTokensFromMessages(messages []openai.ChatCompletionMessage, model string) (numTokens int) {
	tkm, err := tiktoken.EncodingForModel(model)
	if err != nil {
		err = fmt.Errorf("encoding for model: %v", err)
		log.Println(err)
		return
	}

	var tokensPerMessage, tokensPerName int
	switch model {
	case "gpt-3.5-turbo-0613",
		"gpt-3.5-turbo-16k-0613",
		"gpt-4-0314",
		"gpt-4-32k-0314",
		"gpt-4-0613",
		"gpt-4-32k-0613":
		tokensPerMessage = 3
		tokensPerName = 1
	case "gpt-3.5-turbo-0301":
		tokensPerMessage = 4 // every message follows <|start|>{role/name}\n{content}<|end|>\n
		tokensPerName = -1   // if there's a name, the role is omitted
	default:
		if strings.Contains(model, "gpt-3.5-turbo") {
			log.Println("warning: gpt-3.5-turbo may update over time. Returning num tokens assuming gpt-3.5-turbo-0613.")
			return NumTokensFromMessages(messages, "gpt-3.5-turbo-0613")
		} else if strings.Contains(model, "gpt-4") {
			log.Println("warning: gpt-4 may update over time. Returning num tokens assuming gpt-4-0613.")
			return NumTokensFromMessages(messages, "gpt-4-0613")
		} else {
			err = fmt.Errorf("num_tokens_from_messages() is not implemented for model %s. See https://github.com/openai/openai-python/blob/main/chatml.md for information on how messages are converted to tokens.", model)
			log.Println(err)
			return
		}
	}

	for _, message := range messages {
		numTokens += tokensPerMessage
		numTokens += len(tkm.Encode(message.Content, nil, nil))
		numTokens += len(tkm.Encode(message.Role, nil, nil))
		numTokens += len(tkm.Encode(message.Name, nil, nil))
		if message.Name != "" {
			numTokens += tokensPerName
		}
	}
	numTokens += 3
	return numTokens
}

我的打印结果如下
go run main.go 22

使用官方接口返回值如下

请问我应该如何修改才能获得正确的token数量